Difference between revisions of "Switches"

From OpenCircuits
Jump to navigation Jump to search
m (Reverted edits by 59.56.174.199 (Talk); changed back to last version by Russ hensel)
Line 13: Line 13:
  
 
== Relays ==
 
== Relays ==
 +
 +
A Relay is a switch that is turned on and off by an electro-magnet ( actually there are new forms that do not use an electro-magnet ).  Like other switching devices it allows a small amount of power to control a large amount of power.  A nice feature of relays is that there is no electrical connection between the control circuit and the circuit connected to the switch. ( this is called electrical isolation ).  They are often used to let low power digital circuits control normal 110v power in a home.
  
 
== needs cleanup ==
 
== needs cleanup ==

Revision as of 06:44, 17 February 2009

Switch Basics

A switch is often to turn something on or off. In the simplest case it is just a wire that is connected or not. Unplugging an appliance is one way to switch it off. A switch is usually a mechanical device where some sort of handle connects or disconnects conductors inside the switch. Another way of thinking of a switch is that it is like a resistor that sometimes has infinite resistance and sometimes has 0 resistance. A computer keyboard is made of a large number of switches. Some switches stay in the on or off position, others only stay on or off while you switch them, these are called momentary switches. A light switch is normally not momentary, a doorbell switch normally is momentary.

Uses:

  • On Off control
  • Range change, as in a meter
  • Data input

Links


Relays

A Relay is a switch that is turned on and off by an electro-magnet ( actually there are new forms that do not use an electro-magnet ). Like other switching devices it allows a small amount of power to control a large amount of power. A nice feature of relays is that there is no electrical connection between the control circuit and the circuit connected to the switch. ( this is called electrical isolation ). They are often used to let low power digital circuits control normal 110v power in a home.

needs cleanup

varc4tb Switch Terminology _P_T - SPST - SPDT - DPST - DPDT - 3PDT - ....

Relays Relays - Use these to control large power sources that a microcontroller cannot do alone