OpenCircuits - User contributions [en]

AVR

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#REDIRECT [[Microcontrollers#Atmel_AVR]]

[[Category:AVR]]

Talk:Cellular rotary phone

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CodeThatThinks: Redirected page to Cellular Rotary Phone

#REDIRECT [[Cellular Rotary Phone]]

Microcontroller

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#REDIRECT [[Microcontrollers]]

[[Category:Components]]

Microcontroller

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#REDIRECT [[Microcontrollers]]

Microcontrollers

2014-11-12T04:02:54Z

CodeThatThinks: CodeThatThinks moved page Microcontroller to Microcontrollers over redirect

=Microcontrollers=

First, a few definitions:

* a '''CPU''' is something that can execute software programs. The earliest CPUs were built out of many parts, but now most CPUs are in microprocessors.
* a '''microprocessor''' is a kind of single [[Integrated Circuits|integrated circuit]] that includes an entire CPU. In the earliest microprocessors, and some famous kinds of microprocessors still being made, the CPU fills the entire chip, and so require external RAM and ROM/FLASH memory. But now most CPUs sold are in microcontrollers[http://www.circuitcellar.com/library/designforum/silicon_update/3/index.asp].
* A '''microcontroller''' is a kind of microprocessor that, in addition to the CPU, also includes RAM, ROM/FLASH memory, digital I/O, analog to digital convertors, and even comparators on a single die/package.

A microcontroller is a little computer on a single Die/Package. The computer includes a CPU core, RAM, ROM/FLASH, and peripherals including UARTS, A/D converters, SPI, and I2C. Microcontrollers differ from microprocessors in that the microprocessors generally have bigger more powerful central processing units, but need support chips for ram, rom and other peripherals. Most modern microcontrollers use FLASH ram instead of a ROM so they can be programmed over and over. Many modern microcontrollers allow self-flashing to enable bootloading or a firmware update without pulling the chip from the circuit or using a programmer/debugger.

Unlike PCs, which have a wide range of programming languages available, microcontrollers have only a few programming languages available -- C programming language, Basic programming language, Forth programming language, assembly language, and (on a few microcontrollers) Python programming language.

Microcontrollers and microprocessors only understand machine code and compilers regardless of type all translate the program to machine code. Machine code, while tedious to learn and device specific, is the most efficient.

People often have strong opinions about their favorite programming language[http://embeddedadventures.blogspot.com/2008/04/4compilers.html].

==General==

Many hobbyists use microcontrollers, sometimes even multiple microcontrollers, in their [[projects]].
Prices have fallen below $5 for the cheapest 32-bit microcontroller and below $1 for the cheapest 8-bit microcontroller.

''I've written a little about the various kinds of microcontrollers at [http://en.wikibooks.org/wiki/Embedded_Systems/Particular_Microprocessors Wikibooks: Embedded Systems]. --[[User:DavidCary|DavidCary]] 06:15, 10 March 2007 (PST)''

About 55% of all CPUs sold in the world are 8-bit microcontrollers. Over 2 billion 8-bit microcontrollers were sold in 1997.[http://www.circuitcellar.com/library/designforum/silicon_update/3/index.asp]
''(Anyone have more up-to-date statistics?)''

Somebody always thinks their microcontroller is the best microcontroller, so we have listed all of them as best.

== Microchip PIC ==

* [[PIC Links]] A bunch of links to PIC based information and projects
* [[Microchip]] PIC 8 bit FLASH microcontrollers
* [[Microchip]] dsPIC/PIC24 16 bit FLASH microcontrollers
* [[DsPIC30F 5011 Development Board]]
* [[Microchip]] PIC32 32 bit FLASH microcontrollers
* PIC based [[Demo board]]

: ''consider merging the following section to [http://en.wikibooks.org/wiki/Embedded_Systems/PIC_Microcontroller#Which_PIC_to_Use Which PIC to use], to gain the advantages of [http://communitywiki.org/ConsolidateInformation consolidating information].''

Note about choosing a PIC:

The number of PIC models is huge so it is worth saying a few words on how to choose a PIC.

Things to consider as a hobbiest or making a small production run:

* Microchip tends to produce the same chip with minor variations. The exact same chip with the exact same pinout may be available in 8k, 16k, or 32k flash. Spend a few extra pennies and take the best.
* SMT parts take practice to work with, so beginners should focus on DIP package parts with <= 40 pins. On the other hand, SMT parts can yield simpler and smaller PCB designs so they are worth consideration even for a hobbiest.
* Contrary to common sense, older parts are often more expensive then newer parts.
* Consider if a free/student version of a C compiler is availible. Microchip provides free/student student versions for the 18f,dsPIC/PIC24, and PIC32.

List of some of the best PICs for hobby purposes:

{| border="1"
|PIC
|Pin Count
|Important Features
|Typical Use
|-
|PIC12F683
|8
|ADC, I/O PWM, Comparator
|Very Simple Projects/Glue Logic
|-
|PIC16F88
|18
|ADC, I/O PWM, Comparator, UART, I2C/SPI
|General Purpose
|-
|18F2620
|28
|ADC, I/O PWM, Comparator, UART, I2C/SPI
|General Purpose
|-
|18F4620
|40
|ADC, I/O PWM, Comparator, UART, I2C/SPI, 8 Bit Parallel Port
|General Purpose
|-
|18F2550/18F2553
|28
|ADC, I/O PWM, Comparator, UART, I2C/SPI, USB
|USB Connectivity
|-
|18F4550/18F4553
|40
|ADC, I/O PWM, Comparator, UART, I2C/SPI, USB, 8 Bit Parallel Port
|USB Connectivity
|-
|P24FJ64GA002
|28
|ADC, I/O PWM, Comparator (with software selectable pin assignment), 2 UART, 2 I2C, 2 SPI
|General Purpose
|}

Note: J means the PIC is a native 3.3V part. Other PICs will run at 3.3V but only at slower clock speeds.

External Links:

== Atmel AVR ==

Atmel's line of 8 and 32-bit RISC microcontrollers are extremely easy to use and a great choice for beginners. With four series—ATtiny, ATmega, ATxmega, and AVR32—there is a large variety in price, processing power, and size, making it simple to meet a variety of needs. Many small chips are available in a [[DIP]] package that allows for quick prototyping and breadboard use.

Combined with an AVRDragon for about 60€ everybody with a budget of about 70€ is able to build and debug his own microprocessor applications. The AVRDragon allows you to debug all ATmega & ATtiny processors with less than 32k flash using DebugWire or JTAG and to program all ATmega / ATtiny devices using HVPP, ISP and JTAG.

=== [[ATtiny]] ===

Small and somewhat lacking in I/O, but still quite powerful (20MHz System Clock, 20MIPS, 64MHz Fast Peripheral Clock). Ideal for small spaces, limited resources, or a tight budget.

Features include 10bit ADCs, USI, 8/16bit timer, PWM, I²C, SPI , BOD, and WDT.

=== ATmega ===

Middle of the road AVR with a good amount of I/O and a large amount of processing power.

Features include 10bit ADCs, USARTs, 8/16bit timer, I²C, SPI, BOD, and WDT.

Processors:

* ATmega88
* ATmega16/32
* ATmega640/1280/2560
* ATmega1281/2561

=== ATxmega ===

Geared toward application that require a large amount of processing power or a large number of I/O.

Features include 12bit ADC, 12bit DAC, 16 bit timer, USARTs, SPI, I²C, DMA, real time clock, crypto engine.

Processors:

* ATxmega64A1/128A1/192A1/256A1
* ATxmega64A3/128A3/192A3/256A3

=== AVR32 ===

High performance 32-bit microcontroller for multimedia purposes, with system clocks of 200 MHz or more.

Processors:

* AP7000
* AP7001
* AP7002
* AT32UC3A0128/0256/0512

=== Links ===

* [[Arduino Links]] Arduino is a development board based on AVR Microcontrollers
* [[Atmel]] AVR 8 bit FLASH microcontrollers
* [http://www.atmel.com/products/AVR/ Atmel] ATmega & ATtiny
* [http://www.atmel.com/products/AVR/default_xmega.asp Atmel] ATxmega
* [http://www.atmel.com/products/AVR32/ Atmel] AVR 32
* [http://makecircuits.com/blog/2009-03-23-simplest-atmega8-programmer-using-lpt-port.html Simplest AVR programmer Using LPT Port]

== Development Boards ==
Development Boards are printed circuit boards that contain a microcontroller and enough circuitry to get it going, typically at least some of the following: clock, voltage regulator, reset button, communications chip, buffer amplifiers, led's, prototyping area, and/or off chip connections. Sometimes the manufacturer of the chip sells development boards ( often called evaluation boards ). Development boards can be really basic, just enough to make the processor run, with connections to the IO pins. Or the boards can include communications, displays, input buttons etc. Often you can jump start a project by using a development board that does the boring standard stuff and let you focus on your project. The development board can let you use high density parts and surface mount parts that you might not want to mess with. The BitWacker kit from [[SparkFun]] is priced close the to the total price of the parts. This is probably true of some other development boards as well. Note that some development boards require you to build them they have not been made available as kits, some come both ways.

*[[Chalk Roach]] based on AVR Atmega32
*[[Arduino Links]] Arduino is based on AVR Microcontrollers
*[[USB Bit Whacker]] This is a PIC 18 based system ... can be used with [[BitWacker Java Communications]]
*[[RS232 Dev Board]]
*[[dsPIC30F 5011 Development Board]]
* [http://www.gogoboard.org GoGo Board] based on PIC18F4550 (via [http://www.blikstein.com/paulo/index.html Prof. Paulo Blikstein]): "an open-source platform that is designed to be low-cost and allow for local assembly by those who are interested." All parts are through-hole (even the USB connector). KiCAD PCB design files.

Other demo boards: see [[demo board]].

== Cypress PSoC ==

* Cypress PSoC 8-bit and 32-bit FLASH microcontroller + mixed-signal array on one chip.

External Links:
* [http://www.psocdeveloper.com/forums/ PSoCDeveloper] -- friendly electronics discussion forums from beginner to advanced level, but focused on PSoC devices.
* [http://en.wikibooks.org/wiki/Embedded_Systems/Cypress_PSoC_Microcontroller Wikibooks: Cypress PSoC]
* [http://www.sparkfun.com/commerce/product_info.php?products_id=8480 SparkFun: Gainer PSoC Development Board] including USB interface -- looks very similar to the [[Arduino Links | Arduino Nano]], but it can do a lot more.

== ARM ==

* [[Image:lpc2103.jpg|69px|LPC2103]] [http://www.k9spud.com/arm/lpc2103/ LPC2103] Low cost 70MHz ARM7TDMI-S FLASH Microcontroller from Philips. The [http://coridiumcorp.com/arm7/ "$49" "Coridium ARMmite"] does use this chip.
* the [http://www.open-research.org.uk/ARMuC/ ARM microcontroller wiki].

There are no ARM chips currently manufactured in a through-hole package -- they are *all* surface-mount.
However, there are many "adapter boards" aka [[demo board]] that make them easier to use, such as:
* low-cost ARM demo boards at NGX Technologies: [http://shop.ngxtechnologies.com/index.php?cPath=21]
* $10 STMicroelectronics’ STM32 Discovery Kit with ARM® Cortex-M3 microcontroller [http://www.st.com/internet/com/press_release/p3065.jsp] [http://www.st.com/internet/evalboard/product/250863.jsp]
* [[Motherboards that run Linux]]

== further reading ==

* [http://www.instructables.com/id/How-to-choose-a-MicroController/ Instructables: How to choose a MicroController]
* [http://en.wikibooks.org/wiki/Embedded_Systems/Particular_Microprocessors#brief_selection_guide Wikibooks: brief selection guide]
*[http://www.veys.com/index.php?title=Main_Page Main Page] May have been a one man effort, now dropped. Has a bit of content that looks good.
*[http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/ Cornell University ECE 4760 Designing with Microcontrollers Final Projects] A ton on projects.
*[http://forum.allaboutcircuits.com/showthread.php?t=21358 Which uC (Microcontroller)? - discussion]
*[http://www.ladyada.net/library/picvsavr.html PIC vs. AVR Ultimate fight]
* [http://chiphacker.com/questions/1092/whats-the-difference-between-a-microcontroller-and-a-microprocessor Chiphacker: "What’s the difference between a microcontroller and a microprocessor?"]

[[category:microcontroller]][[Category:Components]]

Transformer

2014-11-12T03:53:50Z

CodeThatThinks: Created redirect to transformers

#REDIRECT [[Transformers]]

[[Category:Components]]

Transistor

2014-11-12T03:52:56Z

CodeThatThinks: Added to components category

#REDIRECT [[Transistors]]

[[Category:Components]]

Triac

2014-11-12T03:52:38Z

CodeThatThinks: Updated redirect to match splitting up of pages

#REDIRECT [[Triacs]]

[[Category:Components]]

Other Passives

2014-11-12T03:49:35Z

CodeThatThinks: Split into separate pages

[[Inductors]], [[Transformers]]

[[Category:AFD]]

Transformers

2014-11-12T03:49:02Z

CodeThatThinks: Moved from Other Passives

Transformers are 2 or more inductors where the coils share the same magnetic field. This results in the current in one coil inducing a current in the other. They are commonly used to change the voltage from an AC source to a different voltage. We need much more description and information here. Would you add it?

Comments:

"Ferrites? I don't know much about 'em, I only use ferrites in switching regulators." --National Semiconductor's Bob Pease

Can be replaced in many circumstances with an impedance inverter using only an opamp, a capacitor, and a few resistors.

Inductors

2014-11-12T03:48:26Z

CodeThatThinks: Moved from Other Passives

An inductor is a passive electrical component that can store energy in a magnetic field created by the electric current passing through it. An inductor's ability to store magnetic energy is measured by its inductance, in units of henries. Typically an inductor is a conducting wire shaped as a coil; the loops help to create a strong magnetic field inside the coil due to Ampere's Law. Due to the time-varying magnetic field inside the coil, a voltage is induced, according to Faraday's law of electromagnetic induction, which by Lenz's Law opposes the change in current that created it. Inductors are one of the basic components used in electronics where current and voltage change with time, due to the ability of inductors to delay and reshape alternating currents. Inductors called chokes are used as parts of filters in power supplies or to block AC signals from passing through a circuit.

If the rate of change of current in a circuit is one ampere per second and the resulting electromotive force is one volt, then the inductance of the circuit is one henry.

=== equation here soon ===

units
A = ampere

C = coulomb

F = farad

J = joule

kg = kilogram

m = meter

s = second

Wb = weber

V = volt

Ω = ohm

Uses:
*tuned circuits: a circuit that responds in a special way to some frequencies( s ).
*power supply filter: remove the pulsing DC left from rectification or other noise in the signal.
*Decoupling: usually blocking high frequencies from one part of a circuit from getting in another part.
*boost buck regulators: voltage regulators that decrease or increase voltage.

Links
*[http://en.wikipedia.org/wiki/Inductors Inductor From Wikipedia, the free encyclopedia]

Components

2014-11-12T03:47:35Z

CodeThatThinks: Split up other passive components

Components are the basic building blocks of circuits. An individual component can be thought of as a single physical device in a circuit. We used to think of them as the resistors, capacitors, diodes, and other discrete components that make up our electronics, but as technology has advanced more and more devices have been added to this category. Components can be categorized in a variety of ways. Sometimes this might be by their electrical characteristics, like resistors and capacitors, while other devices, like sensors, are categorized by their use. In some cases this can result in a component that is listed twice. For example, a temperature sensing resistor is both a resistor and a sensor.

Compound components known as [[Modules | modules]] have steadily increased in popularity, making it easier than ever to add specific functionality to a circuit, whether it be in the form of a power supply, wireless radio, or one of the many other types of modules. [[Microcontroller Boards]] are but one example. Integrated circuits are another form of compound components, and there are hundreds of kinds available for a wide range of applications.

In this listing [[Integrated Circuits]], [[Modules]], [[Microcontroller Boards]] are listed as one item, but note that they come in a huge number of flavors with a huge number of purposes.

== Active Components ==
These are components capable of producing or amplifying energy in a circuit.

=== [[Battery | Batteries]] ===
Power Up.

=== [[Diodes]] ===
These devices conduct very differently in one direction versus the other.

=== [[demo board]] ===
Lots of people put a microprocessor and most of the other essential stuff on a tiny little demo board, easy to plug into your solderless breadboard (or your custom PCB) that has just a few more things that make your project special.

=== [[Integrated Circuits]] ===
[[Op amp|Op Amps]], Voltage Regulators, Drivers, Digitally Programmable Potentiometers, [[555 Timers]] ... For motor drivers see Motors below. Lots of parts in a package to do something useful.

=== [[Optoelectronics]] ===
LEDs, photodiodes, optoisolators, LCDs, IR proximity detectors,...

=== [[Microcontrollers]] and [[Microcontroller Boards]] or Modules ===
Little Computers for your entertainment.

=== [[Transistors]] ===
Devices used to switch and amplify electricity.

=== [[Triacs]] ===
Capable of conducting in either direction when triggered.

=== [[Sensors]] ===
Accelerometers, Gyroscopes, Temperature Sensors, Pressure Sensors, ... Find out what is going on.

== Passive Components ==
These components can use and manipulate energy in a circuit, however they cannot add or amplify.

=== [[Resistors]] ===
and Potentiometers Resistance is not futile. In there simplest form passive components, but now some are IC using forming variable resistors and potentiometers.

=== [[Capacitors]] ===
Store charge and energy, block dc, filter. In their simplest form passive components, but now some are IC using switched capacitors to synthesize other and variable values.

=== [[Inductors]] ===
Stores energy in a magnetic field.

=== [[Transformers]] ===
Two coils where one coil induces a current in the other via a magnetic field.

== Electromechanical Components ==
These can carry out electrical processes by using mechanical processes or electrical connections, or have mechanical processes that are driven by electricity.

=== [[Connectors]] ===
Join parts.

=== [[Oscillator]] ===
Crystals, Ceramic Resonators, oscillators, ... Vibrate with excitement.

=== [[Motors]] ===
Make thing move. We include some circuits/chips for driving motors. Servos, steppers, and others.

=== [[Switches|Switches and Relays]] ===
Turn things on and off.

== Other Components ==
=== [[Modules]] ===
GPS, Mobile Phone, RF Transceiver, Bluetooth Modules, ...

=== [[Enclosures]] ===
Cover up.

== [[Popular Parts]] ==
So many parts to pick, but which ones? Why not pick a popular part, or a group of parts for areas of interest?

== Obtaining Components ==
=== [[Manufacturers | Component Manufacturers]] ===
Links to homepages, phone numbers, contact info, ... There is often info under each component as well in the components sections above.

=== [[Free From Salvage]] ===
Dig in, to the free stuff, a list of links and a bunch of ideas on how to use your loot.

=== [[Free Samples]] ===
Free is nice.

=== [[PCB Manufacturers]] ===
Contact info, PCB trace width/spacing capability, ...

=== [[Salvage Ideas]]===
Unusual ideas for the fruits of your labor.

=== [[Suppliers]] ===
Good places to buy, numbers to call, people to talk to, ... Get your low cost motor controller boards & motor driver ICs

=== Fakes ===
Beware!

*[http://sound.westhost.com/counterfeit.htm Counterfeit Index]

== [[Component and Parts Storage]] ==
Proper storage is the key to minimizing damage to parts and ensuring that they will work properly when you need to use them.

== Data Sheets ==
You will want data sheets for you parts. Do not leave home, or start a project without them.

Check:
* original manufacturer
* [[supplier | parts distributor]]
* http://www.datasheetcatalog.com/

== Links ==
*[http://en.wikipedia.org/wiki/Electronic_components Electronic component From Wikipedia, the free encyclopedia]
*[http://www.piclist.com/images/www/hobby_elec/e_parts.htm Basic Components] Quite a few components and some info on use.
*[http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/comp.htm Electronic Components]

[[Category:Components| ]]

Diodes

2014-11-12T03:44:01Z

CodeThatThinks: Added to components category

Diodes are two terminal devices that conduct very differently in one direction verses another. The basic use takes advantage of this property, but the are other characteristics that are also useful and special diodes that take advantage of these properties.

== How They Work ==
At the most basic level, diodes allow current to flow in one direction and prevent current from flowing in the opposite direction. If we take a look at their construction, we can see why this occurs.

Diodes consist of two dissimilar materials that come together at a joint. One material has an abundance of electrons and therefore is negatively charged, while the other lacks electrons and is positively charged. At the junction between the two materials, electrons in the first material are attracted to the electron-less second material, forming a neutral atoms at the center of the junction which act as an insulator.

When current is applied backwards, that is, to the electron-lacking side, electrons in the wire are attracted to the material, pulling it away from the junction. There is a similar effect on the other side, as electrons in the other material are attracted to the electron-lacking atoms in the wire.

If current is applied to the side with an abundance of electrons, the electrons in the wire repel the electrons in the material, pushing the insulating atoms away from the junction. As the atoms are pushed further and further, the diode will get to a state where it begins conducting current.

== Special Types ==
* Schottky
* Zener
* Avalanche
* Tunnel

== Uses ==
Diodes can do many different things. They can detect, rectify, suppress, emit light, change capacitance, emit microwaves, etc.

=== As a Rectifier ===
Changing alternating current to direct current. A standard in almost all plug in power supplies and most electronic circuits run on DC. [http://www.vishay.com/docs/88867/anfundam.pdf Application Note Vishay General Semiconductor]

=== As a Detector ===
As in an amplitude modulated radio ( AM ) where the radio signal is changed to an audio signal.

[[File:diodesnubber.png | frame | right | [[Basic Circuits and Circuit Building Blocks#Relay with Diode Snubber]] ]]
=== As a Snubber ===
Some circuits, typically those with inductance like inductors, [[motor driver | motors]], [[relays]] and solenoids, generate a large back or reverse voltage when they turn off. Often a diode will be inserted to "short circuit" this voltage/current. This can prevent damage to other circuit components.

=== As an Exponential/Logarithmic Converter ===
The current in the forward direction is an exponential function of the voltage. Together with an op amp this can be used to convert voltages to via an exponential or logarithmic function. These in turn can be used for multiplication, division, powers and roots. See [[OpAmp Links]]

=== Clipping, Bias Voltage ( Temperature Sensing ) ===

In the forward direction a junction has about .6 volts when conducting ( as does the base emitter junction of a bipolar transistor ). This voltage is useful as a small well defined voltage for bias in a transistor circuit. Often 2 or more will be used in series for a higher voltage. If the input is a varying voltage the output is equal to the input and then begins to clip ( stop rising ) at about .6 volts. Feeding in a triangle wave at the right amplitude you get out a triangle wave with the points rounded off, an approximate sine wave.
The bias voltage is somewhat temperature sensitive, you can used this in an electronic thermometer circuit.

=== Over Voltage Protection ===
Many circuits cannot tolerate voltage over a certain limit ( often the power supply voltage ). Connecting a diode from the circuit input to the power supply can "short out" the over voltage. Make sure the diode is connected in the proper direction.

=== Bridge ===
This is an arrangement that is used for full wave rectification and some other circuits that are a bit tricky. Not explained here and now but Google will help you out

=== Reverse Protection ===
Many circuits destroy themselves when connected backwards to a voltage source. Connecting a diode in series with the circuit blocks the reverse voltage.
See [[Reverse Protection Diodes]].

=== Voltage Doubler ===
Diodes and resistors can be used to produce high voltages from AC without transformers.
See [http://www.vishay.com/docs/88842/anusingr.pdf Using Rectifiers in Voltage Multiplier Circuits Application Note Vishay General Semiconductor]. We should have a voltage doubler in our basic circuits section, do we?

== See Also ==
* [[LEDs]]
* [[Reverse Protection Diodes]]

== Additional Resources ==
* [http://en.wikipedia.org/wiki/Diode Diode on Wikipedia, the free encyclopedia]
* [http://en.wikibooks.org/wiki/Electronics/Diodes Electronics/Diodes From Wikibooks, the open-content textbooks collection]
* [http://en.wikibooks.org/wiki/Practical_Electronics/Diodes Practical Electronics/Diodes From Wikibooks, the open-content textbooks collection]
* [http://www.allaboutcircuits.com/vol_3/chpt_3/12.htmlSpecial-purpose diodes]

[[Category:Components]]

Diodes

2014-11-12T03:43:06Z

CodeThatThinks: Added information on how they work, cleaned things up a bit

Transistors, Diodes, etc.

2014-11-12T02:56:57Z

CodeThatThinks: Moved to separate pages

[[Transistors]], [[Diodes]], [[Triacs]]

[[Category:AFD]]

Triacs

2014-11-12T02:51:52Z

CodeThatThinks: Moved from Transistors, Diodes, etc.

Capable of conducting in either direction when triggered. Also known as a TRIode for Alternating Current. Useful for AC, often at fairly high current and voltage. May be used as switches and dimmers.
* [http://www.allaboutcircuits.com/vol_3/chpt_7/6.html "All About Circuits: The Triac"]
* [http://en.wikibooks.org/wiki/Power_Electronics#Triacs "Wikibooks: Power Electronics: The Triac"]

Diodes

2014-11-12T02:50:24Z

CodeThatThinks: Moved from Transistors, Diodes, etc.

Diodes are two terminal devices that conduct very differently in one direction verses another. The basic use takes advantage of this property, but the are other characteristics that are also useful and special diodes that take advantage of these properties.

===General===
A diode lets current through in one direction but not another. It acts somewhat an infinite resistance in one direction, and a 0 resistance in the other direction. A more accurate description ( but not complete ) says that in the low resistance direction there must be a .6 v drop before much current flows.

Other Reading
*[http://en.wikipedia.org/wiki/Diode Diode From Wikipedia, the free encyclopedia]

*[http://en.wikibooks.org/wiki/Electronics/Diodes Electronics/Diodes From Wikibooks, the open-content textbooks collection]

*[http://en.wikibooks.org/wiki/Practical_Electronics/Diodes Practical Electronics/Diodes From Wikibooks, the open-content textbooks collection]

*[http://www.allaboutcircuits.com/vol_3/chpt_3/12.htmlSpecial-purpose diodes]

==== Use: Rectifier ====
Changing alternating current to direct current. A standard in almost all plug in power supplies and most electronic circuits run on DC. [http://www.vishay.com/docs/88867/anfundam.pdf Application Note Vishay General Semiconductor]

==== Use: Detector ====
As in an amplitude modulated radio ( AM ) where the radio signal is changed to an audio signal.

[[File:diodesnubber.png | frame | right | [[Basic Circuits and Circuit Building Blocks#Relay with Diode Snubber]] ]]
==== Use: Snubber ====
Some circuits, typically those with inductance like inductors, [[motor driver | motors]], [[relays]] and solenoids, generate a large back or reverse voltage when they turn off. Often a diode will be inserted to "short circuit" this voltage/current. This can prevent damage to other circuit components.

==== Use: Steering ====
Sending a voltage/current in a particular direction in a circuit

==== Use: Exponential/Logarithmic Converter ====
The current in the forward direction is an exponential function of the voltage. Together with an op amp this can be used to convert voltages to via an exponential or logarithmic function. These in turn can be used for multiplication, division, powers and roots. See [[OpAmp Links]]

==== Use: Clipping, Bias Voltage ( Temperature Sensing ) ====

In the forward direction a junction has about .6 volts when conducting ( as does the base emitter junction of a bipolar transistor ). This voltage is useful as a small well defined voltage for bias in a transistor circuit. Often 2 or more will be used in series for a higher voltage. If the input is a varying voltage the output is equal to the input and then begins to clip ( stop rising ) at about .6 volts. Feeding in a triangle wave at the right amplitude you get out a triangle wave with the points rounded off, an approximate sine wave.
The bias voltage is somewhat temperature sensitive, you can used this in an electronic thermometer circuit.

==== Use: Over Voltage Protection ====
Many circuits cannot tolerate voltage over a certain limit ( often the power supply voltage ). Connecting a diode from the circuit input to the power supply can "short out" the over voltage. Make sure the diode is connected in the proper direction.

==== Use: Bridge ====
This is an arrangement that is used for full wave rectification and some other circuits that are a bit tricky. Not explained here and now but Google will help you out

==== Use: Reverse Protection ====
Many circuits destroy themselves when connected backwards to a voltage source. Connecting a diode in series with the circuit blocks the reverse voltage.
See [[Reverse Protection Diodes]].

==== Use: Voltage Doubler ====
Diodes and resistors can be used to produce high voltages from AC without transformers.
See [http://www.vishay.com/docs/88842/anusingr.pdf Using Rectifiers in Voltage Multiplier Circuits Application Note Vishay General Semiconductor]. We should have a voltage doubler in our basic circuits section, do we?

==== Use: Isolation ====

=== Light Emitting Diode ===
The LED see [[LED]]

=== Tunnel Variable Capacitor Trans Diode ===

=== Other Special Types ===

Shockley Junction, Tunnel, variable capacitance.....

==== Photo ====

see [[Sensors]] photo

[[Image:PG31-PowerSupply.jpg|69px]] [[Reverse Protection Diodes]] - PTH and SMD diodes to protect against reverse polarization.

Transistors

2014-11-12T02:49:22Z

CodeThatThinks: Moved from Transistors, Diodes, etc.

Transistors are three termainal devices where one terminal controls the power through the other two. They come in 2 different famlies Bipolar ( a little depressed, but only some of the time ) and Field Effect ( usually metal oxide semiconductors MOS). We have seperate sections for each. This may be useful [http://www.allegromicro.com/en/products/design/technote/bipvsmos.asp Comparison of Power MOS and Bipolar Power Transistors]

== Bipolar Transistors ==
'''TWO TYPES:'''

Bipolar transistors are current controlled devices. The current flowing in/out of base controlls the current flowing in/out of the Collector. There are two basic types of Bipolar transistors: NPN and PNP.

In bipolars, the collector current (Ic) is controlled by the base current (Ib). Ic equals the Ib times a variable called "Hfe" (often listed in transistor datasheets). In other words, Ic = Ib * Hfe. Hfe can range from 30 (for big bipolars) to several hundred.

'''TERMINALS:'''
Collector, Base, Emitter

'''NPN Operation:'''
To turn on and get collector current (Ic) flowing, a small base current must be squirted INTO the base. Do this by raising base voltage through a base resistor. Current flows into collector and out of emitter. If this current is too small (or zero), the base is starved and collector current shuts off. When you squirt enough current into the base, the base-emitter acts like a diode. The way you know you are squirting enough current into the base is by checking the voltage between base and emitter. When transistor is on full, the base will be several hundred millivolts above the emitter voltage (< 500 mV if barely on, usually 600-900 mV when full on).

'''PNP Operation:'''
To turn on and get Ic flowing, a small base current must be pulled OUT OF the base. Do this by pulling base below emitter voltage through a base resistor. Current flows into the emitter and out of the collector. If this current is too small (or zero), the base is starved and collector current shuts off. When you pull enough current out of the base, the emitter-base acts like a diode. The way you know you are pulling enough current out of the base is by checking the voltage between emitter and base. When transistor is on full, the base will be several hundred millivolts below the emitter voltage (< 500 mV if barely on, usually 600-900 mV when full on).

'''Bipolar Smoke Warning: '''
You must limit the curent in bipolar devices. Two ways to do that.
(1) Limit Ib. Use a resistor feeding into the base to limit Ib. Since Ib controls Ic, that will limit Ic. (typical for NPN switching)
(2) Limit Ic. Use a resistor in series with the collector to limit Ic (emitter follower circuit). If you don't limit one or the other, you will get smoke.

If you're not sure which to do, USE A BASE RESISTOR OR BOTH. In a switch, Ib can get large, even if Ic is limited.

'''BIPOLAR SWITCHES vs AMPLIFIER:'''
NPNs and PNPs can be used as switches, buffers or amplifiers. When used as a switch (the easiest), you're cranking the device hard-on or hard-off, nothing in between. Using a transistor as an amplifier requires significantly more design finesse to get linear gain and proper behavior.

'''NPN SWITCH DESCRIPTION:'''
Emitter to ground. Resistor (e.g. 10k) between collector and Vcc. Resistor (e.g. 3k) between input voltage and base. Output = collector voltage. When input goes high (5V, 12V, whatever), transistor turns on, pulls current through collector resistor, and output goes low. When input goes to zero, no current can go into the NPN base. Transistor shuts off, collector voltage pulled to Vcc. When Ic is on fully, voltage between collector and emitter may be around 0.2V.
'''Normal NPN Switching Operation for hobbiests:'''
Emitter tied to ground for switching. Squirt current into base to turn on. Base will be 600-900 mV above the emitter when on. If collector drops below base voltage (saturation in switch operation), the base will start sucking in more current.

'''PNP SWITCH DESCRIPTION:'''
Emitter to Vcc. Resistor (e.g. 10k) between collector and Ground. Resistor (e.g. 3k) between input voltage and base. Output = collector voltage. When input goes to ground, transistor turns on, pushes current through collector resistor, and output goes high. When input goes to Vcc, no current can flow out of the PNP base. Transistor shuts off, collector voltage pulled to Ground. When Ic is on fully, voltage between collector and emitter may be around 0.2V.
'''Normal PNP operation for hobbiests: '''
Emitter tied to Vcc for switching. Pull current out of base to turn on. Base will be 600-900 mV below the emitter when on. If collector rises above base voltage (saturation in switch operation), the base will start sending out more current.

(Bart McCoy, bartomccoy@gmail.com, 3/8/2008)

Links:

*[http://www.piclist.com/techref/transistors.htm?key=base+resistor&from= Transistor Components]
*[http://www.semiconductormuseum.com/Transistors/RCA/OralHistories/Herzog/Herzog_Index.htm EARLY TRANSISTOR HISTORY AT RCA Gerald B. Herzog]

== FET, MOSFET, JFET ==

'''CMOS / MOSFET'''

MOSFET = Metal-Oxide Semiconductor Field Effect Transistor

CMOS = Complementary Metal-Oxide Semiconductor

These are voltage controlled devices. The current is controlled by [[difference]] between the gate voltage (Vg) and source voltages (Vs). When the difference is large enough (above a threshold voltage called Vt (listed in datasheets), the transistor turns on.

'''TERMINALS:'''
Drain, Gate, Source

'''NFETS AND PFETS:'''
Like Bipolar devices, there are two types of FET devices as well. They are built differently.

'''N-Channel FETS (NFETS):'''
NFETS turn on by raising the Gate voltage (Vg) above the Source voltage (Vs). This difference is called Vgs. When Vgs is more than some threshold voltage (Vt), the device turns on. In other words, when Vg is Vt or more volts above Vs, it turns on. Current flows INTO the drain and out of the source. The basic relationship is Id = Constant * (Vgs-Vt)^2. In switching applications or LED control applications, always tie the NFET source to ground. Apply TTL voltage directly to the gate. A resistor is tied between the drain and Vdd. If an LED is used, then the resistor controls the LED current and the LED is placed in series with the resistor.

'''P-Channel FETS (PFETS):'''
PFETS turn on by lowering the Gate voltage (Vg) below the Source voltage (Vs). This difference is called Vsg. When Vsg is more than some threshold voltage (Vt), the device turns on. In other words, when Vg is Vt or more volts below Vs, it turns on. Current flows INTO the source and OUT OF the drain. The basic relationship is Id = Constant * (Vsg-Vt)^2. In switching applications or LED control applications, always tie the PFET source to Vdd. Apply TTL voltage directly to the gate. A resistor is tied between the drain and Ground. If an LED is used, then the resistor controls the LED current and the LED is placed in series with the resistor.

[[Hints]]
Raise a NFET gate up to turn it on. Pull a PFET gate down to turn it on.

'''IMPORTANT NOTE ABOUT MOSTFET GATES:'''
Unlike Bipolar devices, there is ZERO current going in/out of the gate (gate is very high impedance). That means you MUST force the gate voltage where you want it. If left to float, it will move about randomly, turning the transistor on and off unpredictably. If you have a situation where the gate is floating, tie the gate to Ground or Vdd through a large pullup resistor (e.g. 10-20K) to pin down the voltage to a default value of your choice.

'''ANALOGY BETWEEN MOSFETS AND BIPOLAR TRANSISTORS'''

Although Bipolar and FET devices are TOTALLY different, they have "black box" similarities. It is helpful to think about the similaries in how both technologies are used, but they are only for drawing an analogy, not to compare technical operation:

[[Terminals Description:]]
Both are 3-Terminal Devices.

[[High impedance node]]: Collector/Drain

[[Control node]]: Base/Gate

[[Control Reference Node]]: Emitter/Source

[[Turn-On / Turn-Off:]]

Bipolar: Turned on by small base currents flowing in/out of base. A voltage between base and emitter (Vbe) will arise from this current flow. Ic = Ib * Hfe

FET: Turned on by pure voltage (Vgs). Id = Constant * Vgs^2

[[Current-Voltage Relationship:]]

Bipolar: Current turns on sharply with respect to Vbe, exponential-law

FET: Softer turn on with respect to Vgs (square-law)

[[N and P devices:]]

NPN: On when current flowing into base, one diode drop (Vbe) forms between base and emitter. Tie emitter to ground when using as a switch.

NFET: Device on when Vgs gets above Vt. Tie source to ground when using as a switch.

PNP: On when current pulled out of base, one diode drop (Vbe) forms between base and emitter. Tie emitter to Vcc when using as a switch.

PFET: Device on when Vsg gets above Vt. Tie source to Vdd when using as a switch.

==== Other Reading ====

[http://graffiti.virgin.net/ljmayes.mal/comp/vcr.htm The Field Effect Transistor as a Voltage Controlled Resistor]

(Original text Bart McCoy, bartomccoy@gmail.com, 3/8/2008)

===Transistors Transdiode===

This is a connection of a transistor to use it as a diode.

Transistors

2014-11-12T02:45:50Z

CodeThatThinks: CodeThatThinks moved page Transistor to Transistors: Moved to match naming scheme of other component pages

A transistor is a three-terminal device that can be used as an electrically controlled switch, among other things.

Transistor

2014-11-12T02:45:50Z

CodeThatThinks: CodeThatThinks moved page Transistor to Transistors: Moved to match naming scheme of other component pages

#REDIRECT [[Transistors]]

Components

2014-11-12T02:45:03Z

CodeThatThinks: Split Transistors, Diodes, etc. into separate pages: Transistors, Diodes, and Triacs

Components are the basic building blocks of circuits. An individual component can be thought of as a single physical device in a circuit. We used to think of them as the resistors, capacitors, diodes, and other discrete components that make up our electronics, but as technology has advanced more and more devices have been added to this category. Components can be categorized in a variety of ways. Sometimes this might be by their electrical characteristics, like resistors and capacitors, while other devices, like sensors, are categorized by their use. In some cases this can result in a component that is listed twice. For example, a temperature sensing resistor is both a resistor and a sensor.

Compound components known as [[Modules | modules]] have steadily increased in popularity, making it easier than ever to add specific functionality to a circuit, whether it be in the form of a power supply, wireless radio, or one of the many other types of modules. [[Microcontroller Boards]] are but one example. Integrated circuits are another form of compound components, and there are hundreds of kinds available for a wide range of applications.

In this listing [[Integrated Circuits]], [[Modules]], [[Microcontroller Boards]] are listed as one item, but note that they come in a huge number of flavors with a huge number of purposes.

== Active Components ==
These are components capable of producing or amplifying energy in a circuit.

=== [[Battery | Batteries]] ===
Power Up.

=== [[Diodes]] ===
These devices conduct very differently in one direction versus the other.

=== [[demo board]] ===
Lots of people put a microprocessor and most of the other essential stuff on a tiny little demo board, easy to plug into your solderless breadboard (or your custom PCB) that has just a few more things that make your project special.

=== [[Integrated Circuits]] ===
[[Op amp|Op Amps]], Voltage Regulators, Drivers, Digitally Programmable Potentiometers, [[555 Timers]] ... For motor drivers see Motors below. Lots of parts in a package to do something useful.

=== [[Optoelectronics]] ===
LEDs, photodiodes, optoisolators, LCDs, IR proximity detectors,...

=== [[Microcontrollers]] and [[Microcontroller Boards]] or Modules ===
Little Computers for your entertainment.

=== [[Transistors]] ===
Devices used to switch and amplify electricity.

=== [[Triacs]] ===
Capable of conducting in either direction when triggered.

=== [[Sensors]] ===
Accelerometers, Gyroscopes, Temperature Sensors, Pressure Sensors, ... Find out what is going on.

== Passive Components ==
These components can use and manipulate energy in a circuit, however they cannot add or amplify.

=== [[Resistors]] ===
and Potentiometers Resistance is not futile. In there simplest form passive components, but now some are IC using forming variable resistors and potentiometers.

=== [[Capacitors]] ===
Store charge and energy, block dc, filter. In their simplest form passive components, but now some are IC using switched capacitors to synthesize other and variable values.

=== [[Other Passives]] ===
including Inductors and Transformers

== Electromechanical Components ==
These can carry out electrical processes by using mechanical processes or electrical connections, or have mechanical processes that are driven by electricity.

=== [[Connectors]] ===
Join parts.

=== [[Oscillator]] ===
Crystals, Ceramic Resonators, oscillators, ... Vibrate with excitement.

=== [[Motors]] ===
Make thing move. We include some circuits/chips for driving motors. Servos, steppers, and others.

=== [[Switches|Switches and Relays]] ===
Turn things on and off.

== Other Components ==
=== [[Modules]] ===
GPS, Mobile Phone, RF Transceiver, Bluetooth Modules, ...

=== [[Enclosures]] ===
Cover up.

== [[Popular Parts]] ==
So many parts to pick, but which ones? Why not pick a popular part, or a group of parts for areas of interest?

== Obtaining Components ==
=== [[Manufacturers | Component Manufacturers]] ===
Links to homepages, phone numbers, contact info, ... There is often info under each component as well in the components sections above.

=== [[Free From Salvage]] ===
Dig in, to the free stuff, a list of links and a bunch of ideas on how to use your loot.

=== [[Free Samples]] ===
Free is nice.

=== [[PCB Manufacturers]] ===
Contact info, PCB trace width/spacing capability, ...

=== [[Salvage Ideas]]===
Unusual ideas for the fruits of your labor.

=== [[Suppliers]] ===
Good places to buy, numbers to call, people to talk to, ... Get your low cost motor controller boards & motor driver ICs

=== Fakes ===
Beware!

*[http://sound.westhost.com/counterfeit.htm Counterfeit Index]

== [[Component and Parts Storage]] ==
Proper storage is the key to minimizing damage to parts and ensuring that they will work properly when you need to use them.

== Data Sheets ==
You will want data sheets for you parts. Do not leave home, or start a project without them.

Check:
* original manufacturer
* [[supplier | parts distributor]]
* http://www.datasheetcatalog.com/

== Links ==
*[http://en.wikipedia.org/wiki/Electronic_components Electronic component From Wikipedia, the free encyclopedia]
*[http://www.piclist.com/images/www/hobby_elec/e_parts.htm Basic Components] Quite a few components and some info on use.
*[http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/comp.htm Electronic Components]

[[Category:Components| ]]

Components

2014-11-12T02:33:38Z

CodeThatThinks: Divided components up into more specific categories: active, passive, electromechanical

Components are the basic building blocks of circuits. An individual component can be thought of as a single physical device in a circuit. We used to think of them as the resistors, capacitors, diodes, and other discrete components that make up our electronics, but as technology has advanced more and more devices have been added to this category. Components can be categorized in a variety of ways. Sometimes this might be by their electrical characteristics, like resistors and capacitors, while other devices, like sensors, are categorized by their use. In some cases this can result in a component that is listed twice. For example, a temperature sensing resistor is both a resistor and a sensor.

Compound components known as [[Modules | modules]] have steadily increased in popularity, making it easier than ever to add specific functionality to a circuit, whether it be in the form of a power supply, wireless radio, or one of the many other types of modules. [[Microcontroller Boards]] are but one example. Integrated circuits are another form of compound components, and there are hundreds of kinds available for a wide range of applications.

In this listing [[Integrated Circuits]], [[Modules]], [[Microcontroller Boards]] are listed as one item, but note that they come in a huge number of flavors with a huge number of purposes.

== Active Components ==
These are components capable of producing or amplifying energy in a circuit.

=== [[Battery | Batteries]] ===
Power Up.

=== [[demo board]] ===
Lots of people put a microprocessor and most of the other essential stuff on a tiny little demo board, easy to plug into your solderless breadboard (or your custom PCB) that has just a few more things that make your project special.

=== [[Integrated Circuits]] ===
[[Op amp|Op Amps]], Voltage Regulators, Drivers, Digitally Programmable Potentiometers, [[555 Timers]] ... For motor drivers see Motors below. Lots of parts in a package to do something useful.

=== [[Optoelectronics]] ===
LEDs, photodiodes, optoisolators, LCDs, IR proximity detectors,...

=== [[Microcontrollers]] and [[Microcontroller Boards]] or Modules ===
Little Computers for your entertainment.

=== [[Transistors, Diodes, etc.]] ===
Diodes, Transistors are described here. These guys are the basic semiconductors or solid state electronics. ( But not Light Emitting Diodes = LED or Photo Diodes which are listed under Optoelectronics. )

=== [[Sensors]] ===
Accelerometers, Gyroscopes, Temperature Sensors, Pressure Sensors, ... Find out what is going on.

== Passive Components ==
These components can use and manipulate energy in a circuit, however they cannot add or amplify.

=== [[Resistors]] ===
and Potentiometers Resistance is not futile. In there simplest form passive components, but now some are IC using forming variable resistors and potentiometers.

=== [[Capacitors]] ===
Store charge and energy, block dc, filter. In their simplest form passive components, but now some are IC using switched capacitors to synthesize other and variable values.

=== [[Other Passives]] ===
including Inductors and Transformers

== Electromechanical Components ==
These can carry out electrical processes by using mechanical processes or electrical connections, or have mechanical processes that are driven by electricity.

=== [[Connectors]] ===
Join parts.

=== [[Oscillator]] ===
Crystals, Ceramic Resonators, oscillators, ... Vibrate with excitement.

=== [[Motors]] ===
Make thing move. We include some circuits/chips for driving motors. Servos, steppers, and others.

=== [[Switches|Switches and Relays]] ===
Turn things on and off.

== Other Components ==
=== [[Modules]] ===
GPS, Mobile Phone, RF Transceiver, Bluetooth Modules, ...

=== [[Enclosures]] ===
Cover up.

== [[Popular Parts]] ==
So many parts to pick, but which ones? Why not pick a popular part, or a group of parts for areas of interest?

== Obtaining Components ==
=== [[Manufacturers | Component Manufacturers]] ===
Links to homepages, phone numbers, contact info, ... There is often info under each component as well in the components sections above.

=== [[Free From Salvage]] ===
Dig in, to the free stuff, a list of links and a bunch of ideas on how to use your loot.

=== [[Free Samples]] ===
Free is nice.

=== [[PCB Manufacturers]] ===
Contact info, PCB trace width/spacing capability, ...

=== [[Salvage Ideas]]===
Unusual ideas for the fruits of your labor.

=== [[Suppliers]] ===
Good places to buy, numbers to call, people to talk to, ... Get your low cost motor controller boards & motor driver ICs

=== Fakes ===
Beware!

*[http://sound.westhost.com/counterfeit.htm Counterfeit Index]

== [[Component and Parts Storage]] ==
Proper storage is the key to minimizing damage to parts and ensuring that they will work properly when you need to use them.

== Data Sheets ==
You will want data sheets for you parts. Do not leave home, or start a project without them.

Check:
* original manufacturer
* [[supplier | parts distributor]]
* http://www.datasheetcatalog.com/

== Links ==
*[http://en.wikipedia.org/wiki/Electronic_components Electronic component From Wikipedia, the free encyclopedia]
*[http://www.piclist.com/images/www/hobby_elec/e_parts.htm Basic Components] Quite a few components and some info on use.
*[http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/comp.htm Electronic Components]

[[Category:Components| ]]

Talk:Basic Circuit Building Blocks

2014-11-12T01:39:41Z

CodeThatThinks: CodeThatThinks moved page Talk:Basic Circuits and Circuit Building Blocks to Talk:Basic Circuit Building Blocks: Shorter and simpler page title

Talk about basic circuits and BB

Got some ideas?

Hey, can you put the eagle cad schematic sources up? That way other folks can copy and paste for new circuits, or adapt the ones there (need a better meter symbol, for example).

This is russ_hensel who did a lot of this yet unfinished page. I will try to pull something together on the eagle files in the next few days and post it somewhere, but do not get too excited, I had to create some of the parts and I did just enough for the schematic, the internal details and footprints are typically junk.

Update The link is here. ''' [http://home.comcast.net/~russ_hensel/OC/BasicCircuits.zip Formerly Missing Link]'''

It occurs to me that the individual circuits should be broken out into seperate pages. This would make the whole thing a lot easier to work with. [[User:Wackyvorlon|Wackyvorlon]] 23:20, 13 April 2008 (PDT)

== high side switch ==

I find the high-side switch section ([[Basic Circuits and Circuit Building Blocks#Transistor High Side Switch]]) confusing.
The text seems to describe a PNP high side switch (or perhaps a Pfet?), while the diagram shows a NPN high side switch.

I've seen PNPs on the high side in some circuits.
I've also seen NPNs on the high side in other circuits.

Would mentioning both kinds on this page lead to unnecessary confusion?
If so, which kind is the best for the purposes of this page?
--[[User:DavidCary|DavidCary]] 20:06, 2 August 2008 (PDT)

Russ says: I wrote the original and did the schematic, I do not think the text indicates which type of transistor is used? But that aside, I now realize that you are right that either type of transistor can be used. With the one in the schematic you have positive logic in that a + input turns on the switch but requires a drive voltage higher than the power supply. If the reverse polarity transistor is used then a low voltage on the input turns on the switch, this does not require that a voltage higher than the main powersupply be used. With fets I think that the npn and pnp are not as symetrical in price and preformance as for bypolar transistors so the positive logic is the prefered approach with some high side switches incorporating their own charge pumps. Some of this should perhaps be noted on the page, but I would rather do it with external references as I would like to keep the circuits on the page nice and simple ( we could also have a follow up page on the wiki ) In any case I am not sure enough about all this stuff to document it without more research that I do not have time to do now ( lots of summer projects including getting ready for burning man, will any of our wiki members be there? ). The upshot is that the item could be improved, but I am not up for it now.

== High side driver -2nd that motion. ==

As mentioned by another contributor, the "Transistor high side switch" and "Transistor Push Pull circuit" are less than ideal. You state yourself that "these may need to be driven at a higher voltage than the supply", where this often not possible e.g. when under battery power. The PNP tranistor should be the high side driver and the NPN the low side. This way the base voltage requirements are well within the range of the supply. If this inverts the logic level then handle it in software.

Additionally a current limiting resistance in the base is needed, this value is chosen to provide enough current to saturate when the transistor is passing its maximum current. Without the resistance your poor PIC port pin is effectively shorted to ground via diode.

russ_hensel says: I think the earlier comment applies only to the "Transistor high side switch". As for the push pull amp I think it is ok as it stands for a simple circuit. I have seen it in many references. It is basically a dual emitter follower so its input impedance is the input inpedance of the load resistor times the beta which is often high enough to make base resistors unnecessary. It is hardly an ideal circuit as it would normally have cross over distortion because of the 0 bias on both transistors. However as a booster for an op amp circuit where it is inside the feedback loop it can do pretty well. I think ( but not very hard or long ) that reversing the transistor polarities would lead to a feed thru short in the output stage with both transistors conducting with heavy currents for 0 input voltage. A special driver might get over that problem. The output transistors are often darlingtons so we cannot drive to the power supply limits. A Sziklai pair might remove this problem, or higher voltage in the drive circuit could also be used. I did not think of this circuit as output for a pic, it is a bipolar device for analog circuits, although it can be used in some digital applications. To repeat the circuits here are meant to be basic enough to work but with out the bells .... for a carefully designed circuit. However the links for each circuit may link to advanced versions of same, either on the wiki ( where you can write up a version ) or off. Let me know if you think the circuit is actually in error or just simplified ( but still operational ).

Talk:Basic Circuits and Circuit Building Blocks

2014-11-12T01:39:41Z

CodeThatThinks: CodeThatThinks moved page Talk:Basic Circuits and Circuit Building Blocks to Talk:Basic Circuit Building Blocks: Shorter and simpler page title

#REDIRECT [[Talk:Basic Circuit Building Blocks]]

Basic Circuits and Circuit Building Blocks

2014-11-12T01:39:38Z

CodeThatThinks: CodeThatThinks moved page Basic Circuits and Circuit Building Blocks to Basic Circuit Building Blocks: Shorter and simpler page title

#REDIRECT [[Basic Circuit Building Blocks]]

Basic Circuit Building Blocks

2014-11-12T01:39:36Z

CodeThatThinks: CodeThatThinks moved page Basic Circuits and Circuit Building Blocks to Basic Circuit Building Blocks: Shorter and simpler page title

These are circuits and parts of circuits that we see over and over again in larger projects. Understanding a complex circuit is much easier if you understand these building blocks.

Operational amplifier are the basis for many circuit building blocks especially in the range of DC to 1 meg Hz. See [[OpAmp Links]].

== Introduction and Page Status.... ==
( Some of schematics have been drawn in Eagle and the screen captured, use other methods if you wish. Feel free to add your own circuits, as long as they are basic building blocks, there are lots of other places for project circuits. If you get into more advanced circuits, give them their own page and link to them. Some entries are not complete, if the explanation of the circuit does not match the diagram that is a good tip off. )
 
To Do
* Why not put alpha order?
* work on external links

More circuits that would be good to add

*AC Coupling Capacitor / High Pass Filter
*Battery Lamp and Switch
*Diode Rectifier

[http://forum.allaboutcircuits.com/showthread.php?t=32697 Current rating and full wave rectification]
*LM35 Temperature Sensor
*555 Timer astable oscillator
*Current mirrors
*charge pump
*diode for forward drop bias voltage
*diode logical or
*H Bridge

An H bridge is an electronic circuit that causes current to flow in one direction or the other ( from a singel ended power supply ). Often used for motor control [[motor driver]].
It is an electronic double pole double throw switch.
**[http://code.rancidbacon.com/Electronics] See Section on ''H-Bridge''
**[http://roko.ca/robotics/h-bridge-fundamentals H-Bridge Fundamentals]
*integrator
*diode full wave bridge
*RC timer
*RF Mixers
*diode rounding circuit
*row and collumn connection
*sample and hold http://en.wikipedia.org/wiki/Sample_and_hold
*Simple Oscillator circuits
*transformer
*voltage multiplier and voltage doubler

*Tranistor Current Mirror
*[[Colpitts Oscillator]]

Links to basic circuits:

*[http://electricalengineeringforbeginners.blogspot.com/ Donny's Learn Electrical Engineering for Beginners]
*[http://webpages.ursinus.edu/lriley/ref/circuits/circuits.html DC/AC Circuit Reference]
*[http://www.educypedia.be/electronics/analogdiode.htm Educypedia] A web site of links. Lots of material.



== Amplifiers ==
An amplifier is any circuit which has a larger output than input, typically either larger voltage or larger current, or both. Generally larger power out than in. Several of the circuits here are amplifiers, but as these are only basic circuit, many types of amplifiers are omitted here.

See the sections on: Op amp Non Inverting Amplifier, Op amp Unity Gain Buffer ....

*[http://www.amplifiersite.com/ AmplifierSite.com]
*[http://electronicdesign.com/Portals/0/TI_Wp_AudioGuide_Aug2011.pdf Guide to a lot of amplifier and other audio circuits]

== Current Sense Resistor ( Shunt Resistance ) ==

A current Sense Resistor is a low value of resistor that is placed in series with some other circuit. We can then measure the voltage across the resistor to compute the current. If the resistor has a low value compared to other components we can ignore the effect on the circuit. We use the word shunt when the voltage is measured by a device that has a fairly low resistance itself. We then have to do a more careful calculation of how the current is shared by the two devices.

Circuit:
[[Image:shunt.png | Shunt Resistance ]]

Where
*R shunt resistor used to sense the current ( and divert it from the meter ). Usually much less in value than the internal resistance of the meter.
*METER meter or other device used to measure the voltage across the shunt resitor. Often the resistance of the meter is ignored ( if high ).
*BATTERY a battery or other voltage source.
*BULB an incandescent light bulb

Discussion:

In the old days a sensitive meter, say 50 mv full scale, would be used with a set of shunt, some looking like metal bars, to measure a wide range of currents, up to and exceeding 50 amps. Sometimes a meter came with a set of shunts for measuring different currents. See links. A completely different way to measure currents is to use a hall effect sensor.

Links to More information:
#[http://www.scienceshareware.com/bg-current-monitoring.htm Scienceshareware.com's How A Precision Resistor Is Used to Measure / Calculate Current and Power in an Electrical Circuit.]
#[http://www.maxim-ic.com/appnotes.cfm/appnote_number/746/ High-Side Current-Sense Measurement: Circuits and Principles]
#[http://en.wikipedia.org/wiki/Shunt_(electrical) Shunt (electrical) From Wikipedia, the free encyclopedia]
* Other ways to measure current: [[Motor_driver#current_sense]]

== Current Limit or Constant Current ( Transistor Based ) ==

This is a modification of the emitter follower to limit the current output. So if your output stage is an emitter follower you can add current limiting to it. Or given enough input drive, say from a voltage divider it will act as a constant current source.

Circuit:
[[Image:cc_limit.png |thumb|450px| Current Limit or Constant Current ]]

Where
*R1 base resistor to limit base current to transistor Q1.
*R2 current sense resistor used to sense the current and turn on transistor Q2.
*Q1 main transistor supplying the load current.
*Q2 current limiting transistor.

Discussion:

The idea here is that R2 is a current sense resistor. When the sense voltage across R2 reaches about .7 ( for silicon transistors ) Q2 begins to conduct and diverts the base drive from Q1 cutting its output current. So the max. current from the circuit is reached when I*R2 = .7. This circuit can be used to protect amplifiers ( including push pull amps. ), power supplies and other circuits; or it can be used as a constant current circuit. It is not a precision circuit, but it is cheap, simple, and effective circuit.

More information:
#[http://freecircuitdiagram.com/2008/08/27/variable-adjustable-current-limiter-circuit/ Variable (Adjustable) Current Limiter Circuit ] This is a bit more complicated version using a transistor to drive a darlington transistor, with the limit being adjustable.
#[http://forum.allaboutcircuits.com/showthread.php?t=32709 Current Source for Resistance Measurement]
#[http://powerampdesign.net/images/AN-12_The_Problem_with_Current_Limit.pdf The Problem with Current Limit] Discusses this circuit as applied to a power amplifier.
#[http://www.instructables.com/id/Constant-current-LED-Tester/ Constant current LED-Tester] Simple application of the circuit as an LED tester.

== Filter Capacitor / Decoupling Capacitor / Low Pass Filter ==
Circuit:
[[Image:filtercap.png | Filter Capacitor ]]

Where
*D2 is a diode, it lets current pass only in the direction of the arrow.
*R resistor
*Input a source of alternating current ( occasionally DC in which case the whole circuit serves only to protect against a reverse connection.
C1 the first, main, filter capacitor.
C2 the second filter capacitor.

Discussion:
In this circuit C1 is a classic filter capacitor it charges while the diode conducts, it discharges and supplies current when the diode does not. R and C2 are a second stage filter. With R set to 0, it simply adds to the value of C1. With R in the circuit it forms a low pass filter which helps remove the ripple from the power ( at the cost of some voltage drop ). In the old days R would often be a low value inductor which had a similar effect without the voltage drop. A capacitor alone is often put across a circuit component that uses power to supply bursts of current and stop noise from being propagated through the power supply.

The amount of ripple in a simple circuit like this can be determined from the supply frequency voltage, output current, and the capacitance. The amount of time without any input voltage is 1/2f. Given an output current I, the charge transferred is is I/2f. The voltage sag is then just the charge divided by the capacitance, or I/2fC. An inductor added to this circuit will compensate for voltage sag by inducing a voltage if the current starts to drop.



== High Side Switch ==

This circuit switches a load at the high side away from ground. With a simple switch it is easy, just wire the switch into the high side. Using transistors is not so easy. There are integrated circuits that make it easy again. But this is not a basic circuit. Contrast with [http://opencircuits.com/Basic_Circuits_and_Circuit_Building_Blocks#Transistor_Low_Side_Switch Transistor Low Side Switch]

== Light Emitting Diode ( with current limiting resistor ) ==

Use this circuit to light low power LEDs

A light emitting diode can be very sensitive to small voltage changes, just a bit too much voltage and the LED will draw too much current and “burn out”. Thus it is often used with a resistor in series. If we have a 5 volt source of voltage and an LED that is specified for 2.5 volts at 10 ma, then the resistor must have ( 5 – 2.5 ) volts = 2.5 volts and 10 ma. Using ohms law 2.5/10 x 10 ee-3 = 250 ohms.

A transistor low or high side switch can be used with the resistor if your input cannot supply enough current for the LED.

Circuit:
[[Image:ledres.jpg | LED and current limiting resistor ]]

Where
*LED the LED
*R_LED the current limiting resistor
*INPUT voltage source for lighting the LED

More information:
*[http://www.seattlerobotics.org/encoder/mar97/basics.html Very Basic Circuits ]
*[http://www.iguanalabs.com/1stled.htm Learning About Transistors and LEDs ]
*[http://quantsuff.com/index.htm WELCOME TO QUANTSUFF'S CIRCUIT PAGE. Low Voltage, high-efficiency Drivers for LED Lights ]
*[http://www.dnatechindia.com/index.php/Tutorials/8051-Tutorial/LED-Interfacing.html Interfacing LED to 8051 Microcontroller]
*[http://www.evilmadscientist.com/article.php/throw Some thoughts on throwies] interesting notes on the resistor normally used with an LED.

== Op Amp Non Inverting Amplifier ==
Use this circuit where the signal you have is not as large as you want, or cannot provide enough current. It is called non inverting because a positive input produces a positive output ( An inverting amplifier produces a negative output when given a positive input ).

Circuit:
[[Image:opamp_nia.png | Op amp Non Inverting Amplifier ]]

Where
*R1 resistor 1 or any other 2 terminal component, capacitor, inductor, diode....
*R2 resistor 2 or any other 2 terminal component.....
OPAMPA Any general purpose op amp, often connected to + and - power supplies

Discussion:
Gain is = ( R1/R2 ) + 1

More Information:
*[[OpAmp Links]]


== Op Amp Precision Rectifier ==
Draft - Incomplete Use this circuit where you wish to get very accurate rectification. Precision means that most of the usual forward voltage drop of a diode circuit goes away. Results look good down into the mv range.

Circuit:
[[Image:opamp_pr.png | Op Amp Precision Rectifier ]]

Where
*D1 Diode....
*R2 resistor 2 or any other 2 terminal component.....
OPAMPA Any general purpose op amp, often connected to + and - power supplies

Discussion:
more comming

Th

More Information:
*[[OpAmp Links]]
*[http://sound.westhost.com/appnotes/an001.htm Precision Rectifiers Rod Elliott (ESP)]



== Op amp Unity Gain Buffer ==

Use this circuit when you have a signal of high impedance ( can supply only a little current ) that you want to connect to another circuit that draws a significant current ( up to about 10 ma for the typical op amp. ). For example if you wish to measure the output of a voltage divider with a 0 to 1 ma meter a unity gain buffer might be just what you need. This circuit is also know as a voltage follower.

The unity gain buffer has an output voltage just the same as the input voltage. The advantage is that the input circuit does not “feel” the output. That is the input acts pretty much like a very large resistor ( many mega ohms or more ) connected to ground, and the output supplies whatever current ( up to about 10 ma ) is necessary to maintain the output voltage. Here is the circuit:

Circuit:

[[Image:opamp_ugb.png | Op Amp Unity Gain Buffer ]]

Where
*INPUT the input signal you wish to buffer
*RIN the input resistor, often 0 ohms.
*OPAMPA Any general purpose op amp, often connected to + and - power supplies
*RFB the feed back resistor
*OUTPUT the output

Discussion:
The values of RIN and RFB are not very critical and are normally 0 ohms, just a straight connection. The op amp here is a quad or 4 op amp part, we are using just one section of it. Power needs to be supplied to pin 8 and 4 in the usual way for op amps.
This circuit uses very large feedback (unity) and for this reason has poor stability margins. This may cause the output to go into oscillations when connected to certain loads (typically capacitive). Check the datasheet of individual opamps for details and remedies.

More information:
*[[OpAmp Links]]
*[http://en.wikipedia.org/wiki/Buffer_amplifier Buffer amplifier From Wikipedia, the free encyclopedia]
*[http://www.bcae1.com/opamp.htm Operational Amplifiers]
*[http://www.eecs.tufts.edu/~dsculley/tutorial/opamps/opamps5.html Op-Amp Buffer]



== Parallel Circuit ==
In a parallel circuit the current divides and some flows through each component . The key to these circuits is that the voltage is the same in every element of the circuit and the total of the current through each of the components adds up to the total current from the battery. When you use a current meter it is always placed in series with the part of the circuit where you wish to measure the current.

Circuit:
[[Image:parallel.png | Parallel Circuit ]]

Where
*R1 resistor 1 or any other 2 terminal component, capacitor, inductor, diode....
*R2 resistor 2 or any other 2 terminal component.....
*BATTERY a battery or other voltage source

Discussion:

I you have a lot of components that use the same voltage put them in parallel. This is how most lights in a house are wired. Each individual light can be turned on and off without changing the current or voltage in the other lights. With a bit of math you can show that the two resistors act like one resistor of value R = R1 + R2 /( R1 * R2 ). When you need a resistor of a different value than you have you can sometimes “make it up” using a parallel connection of resistors you do have. Two identical resistors in parallel are equivalent to one of half the resistance. A parallel circuit can have more than 2 resistors, there can be 3, 4, ... You can find out more about parallel circuits in the references. This circuit should be contrasted with the Series Circuit. Parallel circuits can also be used with other components, the equations vary, for capicators the capacitances add in a parallel circuit.

More information:
* [http://en.wikipedia.org/wiki/Parallel_circuit Series and parallel circuits From Wikipedia, the free encyclopedia]


== Pull Up and Switch ==

Use this circuit when you want to feed a user input to a digital circuit, for example a PIC input pin.

A pull up is a fairly high value resistor (say 1 to 100 K ohms) that is connected to the positive side of the power supply. This makes the other end of the resistor the same voltage as the power supply (as long as it is connected to a high impedance). The other end of the resistor is connected to a switch that is then connected to ground. When the switch is connected current flow through the resistor drops the entire power supply voltage and the input voltage for the circuit is now 0 (sometimes called active low, since when the switch is active the output is low). Note that a pull up ( just the resistor to V+ ) might be considered a basic circuit by itself. Pull up is sometimes used without the switch to keep a signal high all the time. It can also be connected to any other circuit or component that has ( sometimes ) a much lower impedance than the pull up and can thus force the voltage low.

Circuit:

[[Image:pus.png | Pull Up and Switch ]]

Where
*PUSH_BUTTON_SWITCH is a push button switch
*R_PULLUP is the pull up resistor
*VPLUS_VDD is the power supply voltage

More information:
*[http://www.seattlerobotics.org/encoder/mar97/basics.html Very Basic Circuits]
*[http://www.dnatechindia.com/index.php/Tutorials/8051-Tutorial/Switch-Interfacing.html Interfacing Switch to Microcontroller]
*[http://blog.makezine.com/archive/2009/07/ask_make_pull-up_resistor.html Ask MAKE: Pull-up resistor]

Debouncing Discussion:

We have two groups of solution: Hardware Debouncing Circuit and Software Debouncing Driver

Hardware Debouncing Circuit:

[[Image:Pus_debouncing.PNG | Pull Up and Switch with debouncing ]]
with [http://chungyan5.no-ip.org/open_data/electronic_computer/ui/key_with_debouncing geda circuit], and [http://chungyan5.no-ip.org/open_data/electronic_computer/eda/geda/libs symbols]
*Advantage - Do not occupy the CPU processing power for debouncing, lets CPU to handle more other application task(s)
*Disadvantage - we need to implement the above hardware circuit inside the project

Software Debouncing Driver:
*Advantage - Saving cost & space for nothing debouncing circuit
*Disadvantage - Utilize CPU processing power for debouncing, less time for CPU to handle other application process

===ToDo===
*Software Debouncing Driver
**compile time parameters:
***time delay between each sample
***no. of sample - until all samples
**different type of switches, may be have different above compile time parameters
**API to OS or GUI



== Pull Down and Switch ==
Use this circuit when you want to feed a user input to a digital circuit, for example a PIC input pin. ( like the Pull Up and Switch )

Essentially a Pull Up and Switch "upside down". A pull down is a fairly high value resistor (say 1 to 100 K ohms) that is connected to the ground side of the power supply. This makes the other end of the resistor ground as well. (as long as it is connected to a high impedance). The other end of the resistor is connected to a switch that is then connected to positive side of the power supply. When the switch is connected current flow through the resistor raises the voltage to the digital circuit to entire power supply voltage the input is now 1 (sometimes called active high, since when the switch is active the output is high ). Pull down is sometimes used without the switch to keep a signal low all the time.

Circuit:
[[Image:pds.png | Pull Down and Switch ]]

Where
*R_PULLDOWN resistor which normally keeps the output low ( ground ).
*PUSH_BUTTON_SWITCH switch to make the output high
*VPLUS_VDD a battery or other voltage source

Discussion:
Just a variation on the Pull Up and Switch.

Links:

* [http://roguescience.org/wordpress/?page_id=11 Roguescience Arduino Tutorials 4.2 Pull-up/down resistors, debouncing]




== Rectifier - Power ==
this is a stubb, almost no useful content

Use this circuit when you want to convert AC to DC at significant current in order to provide DC power to another circuit component, it can be also used as a very low precision "precision rectifier". Basically similar circuits are sometimes used as demodulators for AM signals.

Circuit:
[[Image:pds.png | Pull Down and Switch ]]

Where
*R_PULLDOWN resistor which normally keeps the output low ( ground ).

Discussion:

There are many variations of this circuit, sometimes in combination with center tapped transformers, sometimes with multiple diodes ( as in bridge circuits ).

Links:

* []



== Rectifier - Signal and Absolute Vaue Circuit ==
this is a stubb, almost no useful content

Use this circuit when you want to know the peak voltage of an AC of time varying DC voltage of just its absolute value. It typically differes from a power rectifier in that the circuit needs
its own source of power, it does not pass thru the power of the input voltage, it also differes in that the typical voltage drop of the power diode ( in the range of .5 to 2 volts ) is largely eliminated. This is a signal processing circuit.

Circuit:
[[Image:pds.png | Pull Down and Switch ]]

Where
*R_PULLDOWN resistor which normally keeps the output low ( ground ).

Discussion:
There are a ton of ways to do this a common way is to include a diode with a forward voltage drop in the feedback loop of an operational amplifier. There are lots of circuits that can be used, see links for discussion of different circuits and there advantages and dis.

Links:

* [http://www.analog.com/library/analogDialogue/archives/44-04/absolute.html More Value from Your Absolute Value Circuit—Difference Amplifier Enables Low-Power, High-Performance Absolute Value Circuit]
* [http://www.ti.com/lit/an/sboa068/sboa068.pdf PRECISION ABSOLUTE VALUE CIRCUITS By David Jones (520) 746-7696, and Mark Stitt]
* [http://i.stack.imgur.com/kUIO3.jpg Images]





== Relay with Diode Snubber ==

Sometimes you will want to switch an external device on and off with a device that can only source a small amount of current (a microcontroller for example). For this you will need a relay. A relay is a mechanical device with a electromagnetic coil and a metal switch. When the coil is energized, the metal switch will move, completing the circuit.

An inductive element, like the relay coil, is likely to generate an undesired voltage when the current is suddenly stopped. Use a diode (snubber) to dissipate the extra voltage.

The diode is connected in reverse from the normal voltage across the inductor, when the voltage is removed the collapsing field can continue to drive current through the diode without generating a high voltage.

Circuit:
[[Image:diodesnubber.png | Diode snubbber ]]

Discussion:

We are assuming in this circuit that the input does not have enough output to drive the relay directly so we are using a transistor low side switch to increase the drive { see '''Low Side Switch''' on this page ). In the circuit shown, the "input" will come directly from the small current source device (microcontroller output pin). The resistor must be sized correctly, along with the NPN transistor DC current gain, to ensure sufficient current passes through the relay coil to activate it.

Other inductors that might use a diode snubber are transformers, solenoids, dc motors, and of course straight ahead inductors.

More information:

*[[Relays]]
*[http://en.wikipedia.org/wiki/Solid_state_relay Solid state relay]
*[http://en.wikipedia.org/wiki/snubber "snubber" from Wikipedia, the free encyclopedia]
*[http://en.wikipedia.org/wiki/flyback_diode "flyback diode" from Wikipedia, the free encyclopedia]
*[http://en.wikipedia.org/wiki/Relay "relay" from Wikipedia, the free encyclopedia]
*[http://www.dnatechindia.com/index.php/Tutorials/8051-Tutorial/Relay-Interfacing.html Microcontroller] relay interfacing example.

== Three Terminal Regulator ==

Use when you need a regulated voltage and or short circuit protection.

Most circuits run better if the primary power source is a constant fixed voltage. A battery is only a poor approximation to this. Taking a battery or other voltage source ( like a wall wart plug in transformer ) and running it through a voltage regulator transforms it into a good fixed source of voltage. It also generally adds current limiting as short circuit protection. The 7805 is a very common 5 volt regulator.

Circuit:
[[Image:ttr.png | Three Terminal Regulator ]]

Discussion:

The circuit above is very basic. Practical circuits normally include filter capacitors on both the input and the output. Most regulators protect against both over temperature and over current. Regulators come in various voltages both positive and negative. They also vary in maximum current output. There are also adjustable regulators, ways of using regular regulators as adjustable ones, and ways of boosting the current output. The spec sheets often describe how to do these things. Voltage regulators “use up” a couple of volts of the input voltage, low drop out regulators have use less, cost more. It is a good idea to check the specification for any regulator you are going to use. The LM78xx ( positive ) and LM79xx ( negative ) are quite common. Most three terminal devices are "linear" they disappate the excess power in the input as heat, thus they are not very efficient. Switching regulators can be much more efficient, but are not normally 3 terminal devices ( although you and make it one by putting the entire circuit in a box with just 3 wires coming out ).

More information:
*[[Basic Voltage Regulators]]
*[http://en.wikipedia.org/wiki/7805 7805 From Wikipedia, the free encyclopedia]
*[http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html Simple 5V power supply for digital circuits]

== Transistor Low Side Switch ==

Use this circuit when you wish to turn a load on and off with both a low voltage and a low current. Note that neither side of the load is grounded.

A low side switch is one which switches a circuit on and off at the ground or low side of the circuit. The advantage of a low side switch is that when using a transistor as the switch the voltage to drive the transistor is itself a low voltage. It is often the easy way to drive LEDS, motors, and other high current devices from such low power devices as PIC output ports. Low side switches are popular and there are many integrated circuits for them as well as this circuit.

Circuit with switch:

[[Image:low_ss.png | Transistor Low Side Switch ]]

Circuit with transistor:

[[Image:Tran_lss.jpg | Transistor Low Side Switch ]]

Where
*LED is a low power LED
*R_LED is a current limiting resistor for the LED
*Q is a bipolar transistor
*R_1 is a current limiting resistor transistor base current
*VPLUS_VDD is the power supply for the LED

Discussion:
The voltage at the collector of the circuit should fall to a fraction of a volt when the input is high. To acomplish this:

*Compute the value of R_LED using ohms law and the specifications for the LED.
*Compute the current through the LED.
*The transistor must sink the current, it should be equal approximately to the input voltage divided by R1 times the beta of the transistor.

An example calculation would be nice, and will appear later.

This circuit is sometimes called "grounded-emitter configuration". Note that this circuit can be realized with a bipolar transistor or fet. The bipolar transistor has a lower drive voltage ( usually well under 2 volts ) the fet can easily need 10 volts of drive -- use a logic level fet to reduce the drive voltage.

Some characteristics:

*Useful ( with simple circuits and common components ) for currents from a max of a few amps and voltages of 10's of volts.
*Can be very fast, into the Mega Hz.
*Can be very cheap at the low end.
*Small, simple.
*Some integrated circuit drivers like the are basically multiple transistor low side switches.

More Information:
*[http://en.wikipedia.org/wiki/Transistor#Switches Transistor From Wikipedia, the free encyclopedia]

== Transistor High Side Switch ==

Use this circuit when you wish to turn a load on and off with a voltage at a low current. Note that low side of the load is grounded. The voltage to turn on the switch is equal to the supply voltage ( or perhaps just a bit larger )

A high side switch is one which switches a circuit on and off at the supply voltage or high side of the circuit (the high side can be negative, it is a side away from ground). The advantage of a high side switch is that the load is grounded on one side. Compared to the low side switch it needs a higher voltage to drive it, but it also eliminates one resistor of that circuit. It the voltage to drive it is available it may be the circuit of choice. It is often the easy way to drive leds motors and other high current devices from such low power devices as PIC output ports.

Here is a high side switch with a push button:

Circuit:

[[Image:high_ss.png | High Side Switch ]]

Circuit with a transistor:

[[Image:tran_hss.png | Transistor High Side Switch]]

Where
*LED is a low power LED
*R_LED is a current limiting resistor for the LED
*Q is a bipolar transistor
*VPLUS_VDD is the power supply for the LED

The voltage at the collector of the circuit should fall to a fraction of a volt when the input is high. To compute the values in the circuit:

*Compute the value of R_LED using ohms law and the specifications for the LED.
*The current to drive the circuit is approximately the current to drive the load divided by the beta of the transistor.

No resistor is needed into the base of the transistor because as the load draws current the voltage at the base will rise and limit the base current. The input voltage should be about equal to VPLUS_VDD, high compared to that needed for the low side switch.

This high side switch usually requires the base voltage of Q to be VPLUS_VDD plus the turn-on voltage of the transistor to turn all the way on. Another approach to the high side switch that requires a lower turn-on voltage is to use a PNP transistor as the switch. The base of the PNP is pulled up to VPLUS_VDD and connected to the collector of a small signal NPN transistor, Q2. Q2's emitter is connected to ground and its base is connected to the input signal through a current limiting resistor -- now the problem is that a high voltage is required to turn the switch off.

== Transistor Emitter Follower ==

Use this circuit when you have a signal of high impedance ( can supply only a little current ) that you want to connect to another circuit that draws a significant current. The circuit has no voltage gain, but because of the current gain it has a lot of power gain. It is frequently used in the final stage of an amplifier.

This circuit is a variation of the transistor high side switch. The difference is that we typically drive this circuit in a linear way ( all of the voltages between 0 and the supply voltage ) to make it a linear amplifier.

The emitter follower is also called a common collector circuit. The Emitter Follower is basically a high side switch, but when we call it an emitter follower we normally think of it as a linear ( analog ) amplifier, rather than as a switch.

Circuit:

[[Image:tef.png | Transistor Emitter Follower ]]

Where
*R_LOAD represents the resistance of the load
*Q is a npn bipolar transistor
*VPLUS_VDD is the power supply for the Load

The current to drive the circuit is approximately the current to drive the load divided by the beta of the transistor. Use a Darlington connected transistor for a very high beta.

No resistor is needed into the base of the transistor because as the load draws current the voltage at the base will rise and limit the base current.

This circuit will only amplify positive voltages, using a pnp transistor you can amplify only negative voltages. Combine the two ( see push pull amplifier ) you can amplify both positive and negative voltages.

Variation of the circuit include:

*Use of coupling capacitors to amplify ac signals.
*Various other components to bias the transistor.
*Use an op amp buffer with voltage gain at the input, then the emitter follower for high current. In this way a few Milli volts with current on the order of pico amps can drive an output of several volts at an ampere or more.

More information:

*[http://www.mines.edu/Academic/courses/physics/phgn217/lab4/lect7/sld013.htm Emitter Follower]

*[http://en.wikipedia.org/wiki/Common_collector Common collector From Wikipedia, the free encyclopedia]

== Transistor -- Push Pull Circuit ==

Use when you need current gain and need both positive and negative output.

A modification of the “transistor emitter follower” that can give both positive and negative outputs. Based on two transistors one npn the other pnp: one pushes the other pulls.

Circuit:
[[Image:pptrans.png | Push Pull Transistor Circuit]]

Where
*Q1 transistor 1 need not be a TIP41C but does need to be NPN
*Q2 transistor 2 need not be a TIP42C but does need to be PNP
*R_LOAD represents the load, here it is in the emitter, it could also be placed in the collector circuit
*VPLUS_VDD Power supply voltage, positive.
*VMINUS Power supply voltage, negative.

Discussion:
Often there are other components for transistor bias or other purposes. The circuit here is really basic. The common transistors used are so called complementary pairs, similar characteristics but one npn and the other pnp. Note that we need both positive and negative power supplies. You can also put the push pull circuit inside the feedback loop of an op amp to get a high current op amplifier. Push pull amplifies can also be made with other types of transistors, tubes, or other components.

More information:
*[http://www.ecircuitcenter.com/Circuits/pushpull/pushpull.htm Push-Pull Output Stage]
*[http://www.allaboutcircuits.com/vol_6/chpt_6/10.html Class B audio amplifier]
*[http://en.wikipedia.org/wiki/Electronic_amplifier Electronic amplifier From Wikipedia, the free encyclopedia (search on Class B and AB )]

== Transistors -- Darlington connected ==

Use a Darlington transistor connection when you want really high current gain. Gain of 1000 is easily in reach. That is 1 ma to 1 amp
This is a useful connection of 2 transistors that together form a transistor of much larger gain. You can also buy Darlington transistors all packaged in a single case with just 3 connections exposed to the outside.

Circuit:
[[Image:dtrans.png | Darlington Transistor Connection ]]

Where
*Q1 transistor 1 need not be a 2N3565 but does need to be NPN
*Q2 transistor 2 need not be a 2N3565 but does need to be NPN
*R_LOAD represents the load, here it is in the emitter, it could also be placed in the collector circuit
*VPLUS_VDD Power supply voltage, positive.

Discussion:

Often Q1 is a high gain small signal transistor and Q2 a lower gain power transistor. You can use PNP transistors by using a negative power supply. Use a ULN2803 ( or similar chips ) to get 8 darlingtons in one package, useful as low side switches and in conjunction with microcontrollers.
* The above diagram shows a high side switch, but other transistor configurations can also be used.
* PNP transistors can also be used, the important point is that both transistors be of the same type.

More information:
*[http://en.wikipedia.org/wiki/Darlington_transistor Darlington transistor From Wikipedia, the free encyclopedia]
*[http://www.kpsec.freeuk.com/trancirc.htm Transistor Circuits ( search on Darlington )]
*[http://www.ibiblio.org/kuphaldt/electricCircuits/Semi/SEMI_4.html Lessons In Electric Circuits -- Volume III Chapter 4 BIPOLAR JUNCTION TRANSISTORS Darlington pair ( search on Darlington )]

== Transistors -- Sziklai pair ==

Similiar in use to a Darlington transistor connection when you want really high current gain. Gain of 1000 is easily in reach. That is 1 ma to 1 amp This is a useful connection of 2 transistors that together form a transistor of much larger gain. Unlike a Darlington the transistors are of opposite types. The circuit also has some other differences in detail, see the refrences.

Circuit:
[[Image:sptrans.png | Sziklai pair ]]

Where
*Q1 transistor 1 need not be a xxx but does need to be NPN
*Q2 transistor 2 need not be a xxx but does need to be PNP
*R_LOAD represents the load, here it is in the emitter, it could also be placed in the collector circuit
*VPLUS_VDD Power supply voltage, positive.

Discussion:

Often Q1 is a high gain small signal transistor and Q2 a lower gain power transistor. You can use PNP transistors by using a negative power

More information:
*[http://en.wikipedia.org/wiki/Sziklai_pair Sziklai pair From Wikipedia, the free encyclopedia]

== RC Filter ==

The most basic filters are the RC-High Pass and RC-Low Pass filters. The high pass filter removes DC and low frequencies and the low pass removes high frequencies.

'''High Pass''' [[Image:rchighpass.png | RC High Pass Filter]]
'''Low Pass''' [[Image:rclowpass.png | RC Low Pass Filter]]

Both circuits have the same 3dB frequency or the frequency at which the power of the signal is aproximately halved.

<math>
f_\mathrm{c} = {1 \over 2 \pi \tau } = {1 \over 2 \pi R C}
</math>

The way to remember the two circuits is to think about how the capacitor acts at various signal frequencies. At high frequencies capacitors act like wires. At low frequencies capacitors act like disconnections.

An important use of low pass filters is for the anti-aliasing circuity on the input of an A/D converter or the output of a D/A converter. An important use of a high pass filter is to remove the DC offset of a signal. For example, it's possible to use a power supply that is +5 to GND to generate a sin from a D/A converter and use a high pass filter to change the sin to a +2.5 to -2.5 signal at the output.

More information:
*[http://en.wikipedia.org/wiki/Low-pass_filter Low Pass Filter]
*[http://en.wikipedia.org/wiki/High-pass_filter High Pass Filter]
*[http://www.tonnesoftware.com/elsie.html The Windows ® program for electrical filter design and network analysis]

== Series Circuit ==

In a series circuit the current first flows through one component then another and so on. The key to these circuits is that the current is the same in every element of the circuit and the total of the voltage across each of the components adds up to the voltage of the battery. A current meter is always in series with the part of the circuit whose current is being measured.

Circuit:
[[Image:series.png | Series Circuit ]]

Where
*R1 resistor 1 or any other 2 terminal component, capacitor, inductor, diode....
*R2 resistor 2 or any other 2 terminal component.....
*BAT a battery or other voltage source

I you have a lot of components that use the same current put them in series. This is often how LEDs are connected to higher voltages; this also eliminates the need for a current limiting resistor on each LED. With a bit of math you can show that the two resistors act like one resistor of value R = R1 + R2 . When you need a resistor of a different value than you have you can sometimes “make it up” using a series connection of resistors you do have. Two identical resistors in series are equivalent to one of double the resistance. A series circuit can have more than 2 resistors, there can be 3, 4, ... You can find out more about series circuits in the references. This circuit should be contrasted with the Parallel Circuit. A voltage divider is an example of a series circuit.

More information:
* [http://en.wikipedia.org/wiki/Parallel_circuit Series and parallel circuits From Wikipedia, the free encyclopedia]



==Seven segment LEDs==
Use these to display number to a user.

*[http://chungyan5.no-ip.org/vc/trunk/AltiumDesigner6ProjectFiles.zip?root=7segment_LEDs&view=log AltiumDesigner6ProjectFiles]
*[http://www.dnatechindia.com/index.php/Tutorials/8051-Tutorial/7-Seg-Interfacing.html Interfacing Seven Segment to Microcontroller]
i need a clear explanation about schmitt trigger and also need the operation details about that circuit...if i give the input of the schmitt trigger is 0v means what is the output of the circuit?

== Oscillators ==

[[Image:Flip-flop circuit.jpg]]
(is there a better page to discuss oscillators?)

== Power up low active reset circuit ==
Use this circuit with a microcontroller to keep it in reset for a short period of time after the power supply is turned on. Some microcontrollers like this kind of start up. Note that this is really just an application of the RC Filter, also on this page.

[[Image:power_up_low_active_reset_circuit.png]]
[[Image:pular.png]]
*[http://chungyan5.no-ip.org/open_data/electronic_computer/middleware/pwr_up_low_active_reset/ power_up_low_active_reset_circuit]
*[http://spreadsheets.google.com/pub?key=pobKDna9aVYeKjbR-Hf-OIg Result of Resistant to delay time]

== ADC Voltage Protection Circuit ==
The input to an Analog to Digital Converter (ADC) has some issues that need a bit of attention.
The ADC can be damaged by input voltages that are too high or too low.
An op-amp is the best way to protect the ADC.
(Additionally, an opamp circuit can provide amplification (although this example doesn't); it can remove aliasing noise; and it drives the ADC with low impedance, which can be quite helpful).

This Sallen-Key filter is a specialization of '''Op amp Non Inverting Amplifier''' also on this page.

[[Image:Adc.png|thumb|800px|center]]
*This opamp circuit is used to
#provide a low input source resistance to the ADC
#protect ADC. Even when the input signal exceeds the supply/reference voltage (i.e. INPUT > Vcc), the voltage into the ADC input pin is capped at the supply voltage.
*Requirement for the op-amp:
**The op-amp can withstand the input signal beyond the supply voltage, provided that the input current is limited to Imax (e.g. [http://focus.ti.com/lit/ds/symlink/opa4340.pdf OPA4340] Imax = 10mA)
**To reduce noise picked up from the op-amp, use an op-amp with a low Input Voltage Noise Density (measured in nV/√Hz)

*Test conditions:
**Vsignal = 5V
**R1 = 8.2kohm, R2 = 15kohm, C1 = 0.1uF, C2 = 0.22uF
**Measured V+ = 3.8V
**Calculated current = (5-3.8)/23200 = 52uA < 10mA

More Information:
* [[input protection]] circuits
* [http://en.wikipedia.org/wiki/Sallen_Key_filter Wikipedia: "Sallen–Key topology"]
* [http://en.wikipedia.org/wiki/anti-aliasing Wikipedia: "anti-aliasing"] and [http://en.wikipedia.org/wiki/anti-aliasing_filter Wikipedia: "anti-aliasing filter"]]

== Voltage Divider ==
Voltage Divider

We use a voltage divider when we have a voltage that is too big and we just want a fraction ( like 1/3 or .33 ) of it. It is like an amplifier with a gain of less than 1. We use two resistors, the output is always a constant fraction of the input voltage.

Sometimes we use a potentiometer as a voltage divider. This makes the ratio of output to input adjustable. This is how we make a gain control or volume control.

Circuit:
[[Image:vdivide.png | Voltage Divider ]]

Where
*R1 resistor 1
*R2 resistor 2
*POT a potentiometer

The ratio of input to output is: output/input = R2/( R1 + R2 ).

Discussion

The equation assumes that the input source is low impedance and the output is high impedance, if this is not true consider using a buffer on the input or the output ( Op Amp Unity Gain Buffer or Transistor Emitter Follower ) For audio applications a so called “log taper” pot may be used as it better matches the way in which we hear. If you want a calibrated control you may use a precision “10 turn precision” pot.

More information:
*[http://www.seattlerobotics.org/encoder/mar97/basics.html Very Basic Circuits]
*[http://itp.nyu.edu/physcomp/sensors/Schematics/VoltageDivider Voltage Divider]

== Voltage Divider using a Light Dependent Resistor ==

Used to generate a voltage that depends upon light level. With the LDR on the "high side" the voltage will go up when the amount of light goes up.
You need to use a resistor in series with the light dependent resistor, this combination lets a variable current flow through the circuit. The voltage across the resistor will vary with the light brightness ( so will the voltage across the LDR, the two will total the input voltage. ) What size resistor should you use? A rule of thumb: Put the LDR in medium brightness and measure its resistance with a ohm meter. Use that value resistor then in medium light you will get 1/2 the input voltage at the output.

Circuit:

[[File:VdivideLDR.png]]

Where

*Input = 5v from power supply Vcc
*Output = signal to connect what ever addition circuit
*LDR The Light dependent resistor
*R: A resistor as described above.

== Wheatstone Bridge ==
'''Draft'''
Use this circuit when you want to measure the value of a resistor or detect a small change in resistance.

Circuit:
[[Image:wbridge.png | Wheatstone Bridge ]]

Where
*Input1 Input 1 normally + DC
*Input2 Input 2 normally - DC or ground.
*R1 Resistor 1.
*R2 Resistor 2.
*R3 Resistor 3.
*R4 Resistor 4.
*Output1 Output 1 for null reading.
*Output2 Output 2 for null reading.
*Meter Use to detect meter balance = null = 0 reading.

Discussion:

The circuit is basically two voltage dividers with the output taken across the output of each voltage divider. It is in "balance" when the output is 0. This is true when R1/R2 = R3/R4. The output traditionally went to a galvanometer a very high sensitivity meter. Input traditionally was a battery. By using calibrated resistors for R1, R2, and R3 the value of R4 may easily be calculated. The whole circuit including a wide range of precision resistors, the battery and galvanometer was all packaged in an box and sold as a unit. The same principal can be used with components other than resistors and AC for input instead of DC.

More Information:
*[http://itp.nyu.edu/physcomp/sensors/Schematics/WheatstoneBridge Wheatstone Bridge]
*[http://physics.kenyon.edu/EarlyApparatus/Electrical_Measurements/Capacitance_Bridge/Capacitance_Bridge.html Capacitance Bridge] This one is an antique.

== Further Reading ==

* [http://freecircuitdiagram.com/ FreeCircuitDiagram] Lots of circuits, not always so basic, more like projects, but many are quite simple. Some but not elaborate explanation of the circuit.

== General Comments ==

''... do we need another page for not-so-basic circuits such as the Baker clamp ? ...'' I looked it up and would say it is not so basic. So perhaps [[Not So Basic Circuits]] would be a good place to put such things. What do others think? russ_hensel

More not-so-basic circuits:
[http://www.geofex.com/circuits/what_are_all_those_parts_for.htm "What are all those parts for??"] by R.G. Keen. 2002
shows a "simple" noninverting gain circuit,
and explains what all the "extra" parts do.

* Philip C. Todd. "Snubber Circuits: Theory , Design and Application". 1993. [http://www.ti.com/lit/an/slup100/slup100.pdf] has more complex snubber circuits.
* [http://electronics.stackexchange.com/questions/17731/choosing-components-for-a-triacs-snubber "Choosing components for a triac's snubber"] has more complex snubber circuits.

[[Category:Components]][[Category:Schematics]]

Techniques

2014-11-12T01:38:05Z

CodeThatThinks: Cleaned up headings

There are a wide variety of techniques used in electronics.

== Circuit Design ==
* [[Basic Circuit Building Blocks]]

== Prototyping ==
Prototyping circuitboards:

* [[Solderless protoboard]]
* [[Point-to-point]] ([http://en.wikipedia.org/wiki/Point-to-point_construction Wikipedia:Point-to-point construction])
* [[Wirewrap]] ([http://en.wikipedia.org/wiki/Wire_wrap Wikipedia:Wire Wrap])
* [[Dead bug style]]
* [[Manhattan style]]
* Board-less construction, not sure there is a name for it, can be very cool see: http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cmoy-freeform-headphone.html this one is potted in clear plastic.
* [http://www.qrp.pops.net/ugly.asp "Ugly Construction"] (like deadbug... )
[http://www.techlib.com/electronics/construction.html "Construction Ideas"] has nice photographs of the above circuit construction techniques.
[[http://www.geofex.com/Article_Folders/protostyles/proto_styles.htm "Effects Building Techniques"] by R.G. Keen 1999 reviews, compares, and contrasts these techniques for circuit construction -- also a few more.

* [[Stripboard]] (Veroboard): ([http://en.wikipedia.org/wiki/Stripboard Wikipedia:stripboard].)

Most of these techniques are designed to use through-hole devices with pins on 0.1" centers -- and vice versa: most through-hole devices are designed to fit into stripboard or other prototyping board with holes on 0.1" centers.

So how do people prototype something with a surface mount device (SMD)?
* Some people continue to use prototyping boards with 0.1" holes, with a bit of creativity, for some SMT devices ([http://www.flickr.com/photos/nshdot/6034580576/in/photostream/])([http://www.flickr.com/photos/nshdot/6034026371/in/photostream])([http://www.flickr.com/photos/nshdot/6034580678/])([http://www.flickr.com/photos/nshdot/6034045085/in/photostream])
* Some people solder many SMT devices to tiny "generic" "surface-mount prototyping boards", then those tiny boards wired together into a complete system (perhaps also including through-hole parts on a stripboard or solderless breadboard). ([http://www.whitewing.co.uk/protoboard.html "Universal through-hole and SMD prototyping board"]), ([http://www.schmartboard.com/ Schmartboard] [http://tech.groups.yahoo.com/group/schmartboardsv/ Schmartboard forum]), ([http://www.capitaladvanced.com/products.htm "Surfboards"]). Alas, none of these are completely generic for most kinds of SMT parts the way that stripboard is completely generic for almost all kinds of through-hole parts.
* Some people buy a [[demo board]] with the SMT part already soldered to it; then these small boards can be wired into a complete system (perhaps also including through-hole parts on a stripboard or solderless breadboard).
* Sometimes people are forced to build a big custom PCB with precise footprints adapted to that SMD device. (This seems to be what manufacturers that make SMDs expect you to do).

== PCB Design/Fabrication ==
[[Printed Circuit Boards]]

== Soldering Techniques ==
* [[Basic soldering]] -- How to use a soldering iron.
* Surface Mount
** [[Skillet reflow]]
** [[Toaster oven reflow]]
** [[Hot air soldering]]
** [http://en.wikipedia.org/wiki/User:WillWare/Homebrew_surface-mount_construction A few different SMT assembly methods] that you can do at home on a cheap budget
* [[Rework]] -- Techniques for fixing mistakes, or for adding new features to a board that ''almost'' does what you want.
** [http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/302_jumper%20wires.html official NASA recommendations for adding discrete wiring ("jumper wires") to PCBs]

(Have you seen this [http://hackaday.com/2007/06/04/cnc-solder-pastepick-n-place/ CNC solder paste/pick n place] ?)
''Hackaday has lots of other similar articles: [http://hackaday.com/?s=solder+paste search hackaday for "solder paste"]''

(Optional: ) After all the parts are completely soldered down, some people like to spray the board with some kind of conformal coating, or completely seal in the board with some kind of potting compound.
See [http://electronics.stackexchange.com/questions/5095/whats-the-best-way-to-protect-a-board-from-corrosion-in-a-hot-moist-environment "Electronics and Robotics: What's the best way to protect a board from corrosion in a hot/moist environment?"].

== [[Hardware tool | Hardware Tools]] ==
A directory of [[hardware tool]]s that you may find useful.

== [[Software tool | Software Tools]] ==
A directory of [[software tool]]s that you may find useful.

== [[PC-Microcontroller Communications]] ==
Discussion of the various methods to connect a microcontroller or embedded system to a PC...

== Embedded System Programming and Testing ==
To add to the confusion programming in embedded system can mean a person writing a program or a device called a programmer "burning" a program into a chip. This section is for the "burning" meaning of programming.

* Many systems use [[JTAG]] for programming and testing. (Such as [http://en.wikibooks.org/wiki/Atmel_AVR Atmel AVR embedded systems]]).
* Other systems use some other kind of in-circuit programming.
* Some people use [http://en.wikibooks.org/wiki/Embedded_Systems/Bootloaders_and_Bootsectors bootloaders] to make re-programming a little quicker.

-- not sure that this next one is not misplaced ? --
''We're talking about "programming and testing" ? What else do you use to test op-amp circuits?''

* Many people use an [[oscilloscope]] ([[o'scope]]). See [[oscilloscope]] for a list of Keith has made a list of low-cost o'scopesl [http://www.techtravels.org/amiga/amigablog/?p=167 "PC USB logic analyzers that cost under $1000."] for a list of low-cost logic analyzers.

Humans writing a program almost always do it in a language. Here is a section that discusses some of these languages: [[Programming Languages]]

== Driving Motors ==
See [[Stepper Motor Tester]] and [[motor driver]].

== Enclosure ==
* The Earth Signal should short to whole metal Case
* Digital/Analog GND should separate to this Earth Signal, and should connect a Y-cap. to filter the noise between them.
* Attention: do not place near between Earth Signal and Digital/Analog GND, otherwise some spark come out, and affect your whole system.
* ''See [[enclosures]]''.

== Misc Tips Tricks ==
[[Misc Tips Tricks]]

== Further Reading ==
* [http://airborn.com.au/method/ "Electronics Design" from Airborn] gives an overview of the complete process: specification, (schematic) circuit design, layout, prototypes, firmware, pilot run, production.
* EDA electronic design automation software is a subset of CAD in general. Is there a wiki that discusses CAD in general? Until I find it, I'm going to post these tools here: "Google SketchUp is a powerful yet easy-to-learn 3D software tool" http://sketchup.google.com/ ; "Inkscape is the best tool for SVG standard vector graphics" http://wiki.inkscape.org/ ; Visual Wiki http://visualwiki.org/
* [http://www.national.com/rap/Story/0,1562,18,00.html "What's All This Ground Noise Stuff, Anyhow?"] by Robert A. Pease
* [http://www.elecdesign.com/Articles/ArticleID/6150/6150.html "What's All This Teflon Stuff, Anyhow?"] by Robert A. Pease -- explains a situation using lots of metal (instead of carefully insulating everything with lots of Teflon) causes less noise. Also mentions "why am I telling you all of these details? If I design a tester with greatly improved performance to help me test a really high-performance product, why should I tell all our competitors so that anybody in the world can test their products using the improved tester? Why should I give away all of these hard-earned secrets?" and gives some very good reasons.
* [http://groups.google.to/group/sci.electronics.design/browse_thread/thread/889153f0e77b1718/fcaac532bb6d4b12?fwc=1 sci.electronics.design: EDN: Measuring Nanoamperes] discusses some ways to measure extremely small currents.
* [http://www.millpcbs.com/ MillPCBs.com for techniques on using a small cnc machine to mill PCB's]
* [http://groups.yahoo.com/group/Homebrew_PCBs yahoo.com/group/Homebrew_PCBs]
* [http://www.electricstuff.co.uk/pcbs.html electricstuff.co.uk/pcbs]
* [http://www.fullnet.com/~tomg/gooteepc.htm fullnet.com/~tomg/gooteepc]
* Dave McGuire says "The notion that through-hole soldering is easier than soldering surface-mount devices is, and always has been, [http://archives.seul.org/geda/user/Aug-2004/msg00175.html a myth.]" (Now, about keeping all the look-alike passive parts straight... :) )
* [http://www.instructables.com/id/Intro-into-SMD-Soldering/ Intro into SMD Soldering]
* [http://PMinMO.com/ PMinMO.com is THE PLACE for DIY CNC driver information]
* [http://uptownmaker.blogspot.com/2009/07/18-essential-skills-for-maker.html 18 Essential Skills for a Maker]

== Environmental Issues ==
See [[better for the environment]].

[[Category:Techniques]]

Popular Parts

2014-11-04T01:43:50Z

CodeThatThinks: Added Dangerous Prototypes' partlist to external links

With so many different parts available, it can be hard to figure out which component to use. Taking a look at what others regularly use might make this process easier.

Note that links may or may not be to the best source. Look around, add a link if you find a better one. Do not delete a link, unless product is gone for good.

== Kits and Projects ==
If you're working from a kit or published project consider getting extras of the parts. The authors of these things tend to know, and pick, what's popular. If you use them once you may use them again; there are exceptions, though.

== PICs ==
Because PICs are mostly digital logic, if you use PICs you will need most of the stuff in the [[Popular Parts#X=Digital Logic]] section as well as stuff in this section.

{| class="wikitable"
|-valign="top"
! What
! Comment
! Specific Part



|-valign="top"
|The PIC
|
* [[microcontroller#Microchip_PIC]]
*[http://www.voti.nl/swp/ Starting with PICmicro controllers] See the Selecting a PIC Section. I like the 16F877, but this may be out of date.
*[http://www.sparkfun.com/commerce/categories.php?cPath=51_22 Selection of PICs]
|
*16F877A
*18F2553 [http://www.raccoonrezcats.com/rfethernet.html]
*18Fxxx

|-valign="top"
|Debugger
|
I don't recommend wasting time on pure programmers for development purposes. Once you get past the blinking LED stage, you are going to need a debugger.
|
*RealICE - Mid to High End PICs
*ICD2 - Broadest range
*Pickit2 - Low to Mid range PICs



|-valign="top"
|
Proto Board
|
Some People hate them, but many find them a nice quick way to experiment. I have found a max clock speed of 4 megHz works well.
[http://www.futurlec.com/Breadboards.shtml Breadboard]
|see links



|-valign="top"
|
Crystals
|
I keep 4 megHz and 20 meg Hz on hand. Note that some PICs can do without crystals, but timing is not very accurate. Check your spec. sheet, some PICs may be able to go to 40 meg Hz. Note that a couple of capacitors are needed as well. Ceramic resonators may be used instead.
*[http://www.sparkfun.com/commerce/product_info.php?products_id=534 Crystal 20MHz]
|
*4 meg Hz
*20 meg Hz


|-valign="top"
|
Pull Up Resistors
|
Can be used as pull down as well. I use 10k ohms, often useful for other stuff as well.
*[http://www.futurlec.com/Res14WMF.shtml Metal Film 1%] 10 for 20 cents.
|
10K


|-valign="top"
|
Generally Useful Chips
|

*[http://chiphacker.com/questions/2320/what-are-the-best-useful-variety-ics-to-have-around-for-pic-microcontrollers What are the best useful variety IC’s to have around for PIC Microcontrollers?] from ChipHacker
|
na




|-valign="top"
|Op Amp

|Need to condition your inputs? a op amp may be just the thing. See section on [[Popular_Parts#X.3DOp_Amps|op amp]]s.
|--

|-valign="top"
|LED

|How else can you say hello world? Pretty much anything will do. Do not forget to get a current limiting resistor 220 ohms or anything close. LED also come in arrays and as 7 segment displays for numerical read out.
|
*220 ohms


|-valign="top"
|Push Button
|Need this for input. I get mine from salvage. Later I will find a source for you.
*[http://www.sparkfun.com/commerce/product_info.php?products_id=97 Mini Push Button Switch]
*[http://www.futurlec.com/Switches/TACT001.shtml TACT001 - Small Black Tactile Switch]
|
*see links


|-valign="top"
|Low Side Switch, Driver Chip

|When you need more power from an output port this is the way to get more than 10 times a much current, Not very expensive. One chip will drive 2 stepper motors. ULN2803 has 8 inputs and outputs.
*[http://www.futurlec.com/ICLinearOthers.shtml ULN2803A]
*[http://www.sparkfun.com/commerce/product_info.php?products_id=312 Darlington Driver 8-Channel ULN2803 DIP ]
|ULN2803


|-valign="top"
|High Side Switch Driver Chip

|Like a low side switch, but on the high side. If you are driving "rows and columns" then you need some on the low side some on the high side. The UDN2981 has 8 inputs and outputs.
*[http://www.futurlec.com/ICSFOthers.shtml UDN2981A]
|UDN2981


|-valign="top"
|Sensors
|There are so many, for light photo diodes and transistors, for temperature LM34 and similar see section on [[Sensors]].
|*whatever


|-valign="top"
|LCD Display

|Put out full alpha numeric data, several characters. Seems like a better? solution than LED when many characters are required. Probably best used with a controller to keep use reasonably simple.
*[http://www.sparkfun.com/commerce/product_info.php?products_id=255 Basic 16x2 Character LCD STN - Black on Green]
*[http://www.piclist.com/techref/io/lcd/panel1.htm LCD Front Panel Set]
|*HD44780 parallel interface



|}

== Op Amps ==
{| class="wikitable"
|-valign="top"
! What
! Comment
! Specific Part

|-valign="top"
|[[op amp]]s
|consider ... what,
|
*358 dual
* [http://www.ladyada.net/rant/2006/02/specifying-an-op-amp/ "Specifying an op-amp"]
* "TL08x series op amps (single, dual, quad) … when you want to have a stash of opamps for prototyping, [http://www.ladyada.net/rant/2006/03/cotw-tl08x-series-op-amps-single-dual-quad/ these are your best bet]."
* LM386N-3 speaker driver
* [http://forum.allaboutcircuits.com/showthread.php?t=11847]

|-valign="top"
|Proto Board
|Some People hate them, but many find them a nice quick way to experiment.
|?


|-valign="top"
|Resistors

|For precise gain you need 1 percent resistors. I start with 10k and use multiples and sub multiples.
|
*10k
*20k
*100K


|-valign="top"
|trim pots
|When you need a bit of adjustability.
|
*10k

|-valign="top"
|diodes
|When you need current one way, not the other. See [[Transistors, Diodes, etc.]] for details.
|
* ''(FIXME: isn't this already too many? Trim.)''
* MBRA140 (1 A DC forward; 40 V reverse) SMT for [[Reverse Protection Diodes]]
* 1N914 (300 mA DC forward; 75 V DC reverse)
* 1N4148 (0.2 A DC forward; 100 V reverse) TH glass
* 1N5711 (0.015 A forward; 70 V reverse) TH glass Schottkey diode
* 1N5817 (1 A DC forward; 20 V reverse) TH Schottkey diode TH $0.15
* BAT48 Schottkey diode (0.35 A DC forward; 40 V reverse)
* BAT85 Schottkey diode (0.20 A DC forward; 30 V reverse)
* 1N5406 (1N5408 is better) (3 A DC forward; 600 V reverse) TH $0.25
* 1N4001 (1N4007 is better) (1 A DC forward; 50 V reverse) TH $0.10
* 1N1188 (1N1189A is better) (35 A DC forward; 400 V reverse) threaded stud ($5.00 Newark 2010)
* 40EPF12PBF (40 A DC forward, 1200 V reverse) ($3.50 Newark 2010)



|-valign="top"
|Power Transistors
|An op amp might be good for 20 mA. Couple it to a darlington transistor and get a full ampere (1000 mA). You may want to go push pull with a pair of npn and pnp transistors. With this you can build power supplies, battery chargers, [[motor driver]]s, and audio amplifiers.
|TIPsomething


|-valign="top"
|Sensors

|Measure something. See [[Sensors]].
|[[Sensors]]


|}

== Digital Logic ==
If you use any microcontroller, you will probably also need most of the stuff in this section.

{| class="wikitable"
|-valign="top"
! What
! Comment
! Specific Part



|-valign="top"
|Gates
|
|
*
* 74HC132 Quad 2-in Schmitt-trigger NAND gate



|-valign="top"
|
Counters
|
* If you use a microcontroller in your project, the counters inside that microcontroller will probably be all the counters you need.

|
*?



|-valign="top"
|
Shift registers
|
Often used to expand the number of ports.
|
*?
* 74HC595 -- for more output pins. SIPO eight bit shift register with output latch. Perfect for letting the propeller clock [[POV display]] slowly clock in the next value, then LOAD them all at once. Near the bottom of the page describing the [http://www.robotroom.com/Tach.html "Digital Numeric LED Displays Tachometer (RPMs), Temperature, and Counter"] project, David Cook says: "The 595 is a great 8-bit serial chip because data can be shifted in without affecting the existing output. All new data is then switched over at the same time. The 595 can also be daisy chained. In this case, 48 outputs are controlled with only three wires (data, clock, and latch)."
* 74HC166 -- for more input pins. PISO 8-bit parallel-load shift registers.
* 74HC165 -- for more input pins. PISO 8-bit parallel-load shift registers.





|-valign="top"
|Voltage Regs
|Power to the Chips
|
*LM7805


|-valign="top"
|
Voltage Reg
|
Easy choice is LM7805. A couple of caps usually go with it. .1 and .01 bypass caps are generally useful.
*[http://www.sparkfun.com/commerce/product_info.php?products_id=107 Voltage Regulator - 5V]
*[http://www.futurlec.com/ICLinearRegulators.shtml 7805T]
|
*7805
*.1 uf
*.01 uf


|-valign="top"
|
decoupling capacitors.
|
"I can only recall using less than 1uF decoupling cap in one circuit in the last 8 or so years ... 100nF bypass caps [0.1 uF bypass caps] are so 1990s. If someone tells you that should be the standard value, you should be careful about what other bad or outdated advice they may be dispensing." -- [http://massmind.org/techref/postbot.asp?by=thread&id=%5BEE%5D+1%2E0+uF+Decoupling+Cap+%2D+A+Must%3F&w=body&tgt=post one post in the PICList Thread (EE) "1.0 uF Decoupling Cap - A Must?"] by Olin
|
* 1uF through-hole caps for solderless breadboard
* 1uF 0805 ceramic caps for [[dead bug style]] prototyping and custom PCBs



|}

== Electric Motors ==
See [[motor driver]] for details.

transistor

"my favorite International Rectifier FU5505 power MOSFET transistor"
-- [http://www.robotroom.com/DualFan.html David Cook]

== External Links ==
*[http://eeshop.unl.edu/storlist.html The Big List These are the parts the EE Shop keeps in stock to sell to students.] UNL likes them why not us?
*[http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-301Solid-State-CircuitsSpring2003/Tools/ This section contains circuit examples from commercial products and datasheets of transistors which are studied in this course. ] If MIT studies them, maybe they are worth looking at.
*[http://www.edn.com/archives/1995/052595/11dfcov.htm Choosing an op amp: it's no longer a trying task] The oldies in particular may be good, but not expensive parts.
*[http://www.voti.nl/swp/ Starting with PICmicro controllers] See the Selecting a PIC Section
* [http://dorkbotpdx.org/wiki/recommended_parts_parts_store DorkbotPDX: Recommended Parts]
* John C Luciani Jr. answers [http://wiblocks.luciani.org/FAQ/faq-parts-list.html "What parts would you recommend stocking?"]
* [http://www.ladyada.net/wiki/partselector Partfinder from ladyAda]
* [http://dangerousprototypes.com/docs/Partlist] Dangerous Prototypes' list of common parts

[[Category:Components]]

Popular Parts

2014-11-04T01:40:19Z

CodeThatThinks: Cleaned up

Components

2014-11-03T23:25:56Z

CodeThatThinks: Moved component storage link to heading

Components are the basic building blocks of circuits. An individual component can be thought of as a single physical device in a circuit. We used to think of them as the resistors, capacitors, diodes, and other discrete components that make up our electronics, but as technology has advanced more and more devices have been added to this category. Components can be categorized in a variety of ways. Sometimes this might be by their electrical characteristics, like resistors and capacitors, while other devices, like sensors, are categorized by their use. In some cases this can result in a component that is listed twice. For example, a temperature sensing resistor is both a resistor and a sensor.

Compound components known as [[Modules | modules]] have steadily increased in popularity, making it easier than ever to add specific functionality to a circuit, whether it be in the form of a power supply, wireless radio, or one of the many other types of modules. [[Microcontroller Boards]] are but one example. Integrated circuits are another form of compound components, and there are hundreds of kinds available for a wide range of applications.

In this listing [[Integrated Circuits]], [[Modules]], [[Microcontroller Boards]] are listed as one item, but note that they come in a huge number of flavors with a huge number of purposes.

== Types ==
=== [[Battery | Batteries]] ===
Power Up.

=== [[Capacitors]] ===
Store charge and energy, block dc, filter. In their simplest form passive components, but now some are IC using switched capacitors to synthesize other and variable values.

=== [[Connectors]] ===
Join parts.

=== [[demo board]] ===
Lots of people put a microprocessor and most of the other essential stuff on a tiny little demo board, easy to plug into your solderless breadboard (or your custom PCB) that has just a few more things that make your project special.

=== [[Enclosures]] ===
Cover up.

=== [[Integrated Circuits]] ===
[[Op amp|Op Amps]], Voltage Regulators, Drivers, Digitally Programmable Potentiometers, [[555 Timers]] ... For motor drivers see Motors below. Lots of parts in a package to do something useful.

=== [[Optoelectronics]] ===
LEDs, photodiodes, optoisolators, LCDs, IR proximity detectors,...

=== [[Oscillator]] ===
Crystals, Ceramic Resonators, oscillators, ... Vibrate with excitement.

=== [[Other Passives]] ===
including Inductors and Transformers

=== [[Microcontrollers]] and [[Microcontroller Boards]] or Modules ===
Little Computers for your entertainment.

=== [[Motors]] ===
Make thing move. We include some circuits/chips for driving motors. Servos, steppers, and others.

=== [[Modules]] ===
GPS, Mobile Phone, RF Transceiver, Bluetooth Modules, ...

=== [[Resistors]] ===
and Potentiometers Resistance is not futile. In there simplest form passive components, but now some are IC using forming variable resistors and potentiometers.

=== [[Transistors, Diodes, etc.]] ===
Diodes, Transistors are described here. These guys are the basic semiconductors or solid state electronics. ( But not Light Emitting Diodes = LED or Photo Diodes which are listed under Optoelectronics. )

=== [[Sensors]] ===
Accelerometers, Gyroscopes, Temperature Sensors, Pressure Sensors, ... Find out what is going on.

=== [[Switches|Switches and Relays]] ===
Turn things on and off.

== [[Popular Parts]] ==
So many parts to pick, but which ones? Why not pick a popular part, or a group of parts for areas of interest?

== Obtaining Components ==
=== [[Manufacturers | Component Manufacturers]] ===
Links to homepages, phone numbers, contact info, ... There is often info under each component as well in the components sections above.

=== [[Free From Salvage]] ===
Dig in, to the free stuff, a list of links and a bunch of ideas on how to use your loot.

=== [[Free Samples]] ===
Free is nice.

=== [[PCB Manufacturers]] ===
Contact info, PCB trace width/spacing capability, ...

=== [[Salvage Ideas]]===
Unusual ideas for the fruits of your labor.

=== [[Suppliers]] ===
Good places to buy, numbers to call, people to talk to, ... Get your low cost motor controller boards & motor driver ICs

=== Fakes ===
Beware!

*[http://sound.westhost.com/counterfeit.htm Counterfeit Index]

== [[Component and Parts Storage]] ==
Proper storage is the key to minimizing damage to parts and ensuring that they will work properly when you need to use them.

== Data Sheets ==
You will want data sheets for you parts. Do not leave home, or start a project without them.

Check:
* original manufacturer
* [[supplier | parts distributor]]
* http://www.datasheetcatalog.com/

== Links ==
*[http://en.wikipedia.org/wiki/Electronic_components Electronic component From Wikipedia, the free encyclopedia]
*[http://www.piclist.com/images/www/hobby_elec/e_parts.htm Basic Components] Quite a few components and some info on use.
*[http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/comp.htm Electronic Components]

[[Category:Components| ]]

EUR

2014-11-03T23:17:41Z

CodeThatThinks: Pages on currencies shouldn't be on Open Circuits, go to wikipedia for that

[[Category:AFD]]

Minimig Resellers

2014-11-03T23:17:15Z

CodeThatThinks: Pages on currencies shouldn't be on Open Circuits, go to wikipedia for that

* [http://www.acube-systems.biz/eng/index.php ACube systems] 080229 138 EUR
* [http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=777 AmigaKit] 080229 115 GBP
* [http://www.vesalia.de/e_minimig.htm Vesalia Computer] 080304 160 EUR

User:WPQEloise

2014-11-03T23:06:46Z