Photoetching

traffiphot link site homepage perizoma uomo mivar 25 mf101 ruote link spartiti jazz whiet town homepage val di nizza url foto di gigliola cinguetti hallelujah rufus wainwright comunita terapeutica ca d andrea stampanti per cd inkjet dior 3088 index calendario 2005 con paola perego matt hardcore www educacion yucatan gob mex resta come sei digimon battle spirit incontri a chiavari porloschicos com site condizioni meteo lazio parkingsex distruttivi homepage michell x2 la minaccia pc orgia em fortaleza site monitor lcd auto mercedes ml 320 sport site muel heli attack 3 il conte ugolino homepage link modem 128 index homepage modem adsl wifi video squali index stock cosmetica henry rollings sexsex and nude women homepage page il bunker del terrore amore ipossibile digital camera dc e300 homepage eamon dont want to back adattatore usb per porta joystick incontri citta di pisa hotel national rimini fisting lesbo map faber castell bicolore bangalore il paradiso delluomo huichapan hidalgo mexico yale limerick ristorante tomoyasu zalman cnps7000b cu canon stampante pixma i 4000 url bravo gt 100 video black eyed peas hey mama maglia kaka eten accessori pisello site km0 fiat multipla auto km 0 italia maglia concorsi letterari s giuliano milanese homepage jeans roberto cavalli url home site intel 770 pajero 3 2 idropulitrici lavorwash site ey j1202 001 la mia gente global ripetitore eminem when i m gone wetar homepage site audiodream 512 Annuncio moto Biglietti invito battesimo Psicologi Mature woman Macchina tempo Culi di donne nere Parco nazionale yosemite Mature vogliose Tatuaggi stilizzati Base van basco Noleggio furgoni bologna Enamonline it Maliziosa chanel Trading azioni Carrello elevatore diesel Filmulete porno gratis Dalida 1996 perugia Playtex Www puntosesso it Pornostar bionde Lea di leo Pianeta escort Antonella elia Timeshare resales Gigi finizio Gommone fuoribordo usato piemonte suzuki Scary movie Video amatoriali sexy Offerta albergo santorini Gnocchi alla romana Impastatrice imperia Fisting gratis Hentay x Adolescenti troie Joystick accessorio xbox consolle Matura moms vs young Fotomodelle Soluzione videogioco saturn Penis enlargement pill Video gratis culi Listini prezzo orologio Verifica velocita adsl Fica gratis Luisa corna Frasi amicizia glitter Cucciolo terranova Accompagnatore solo uomo Ricetta e struzzo Sexi bar corrado fumagalli Auto elaborate mostro Soccerstand Dagosex Compex fitness Footjob Ionamin Finasteride Richiesta finanziamento on line Campagna toscana Mogli cuckold Hotel augusta siracusa Bestiality sex Foto paris hilton Video parto naturale Cazzi gay neri Cerco lavoro san severo Homer simpson Parole crociata online Visure cciaa Manufatti cemento Privata voyeur Dosaggio prolattina Animazione turistica Cisti renali Foto rubata Mandare sms cellulare Hotel economico budapest Adesivi moto Lavelli Arma taggia Arcaton escort Fine settimana Testo della paranza Cabo san lucas ristorante Porno bondage Olatore compex Costellazioni Provini casting Agriturismo siracusa sicilia Trans nere Programma antivirus Alpino Divertirmi ragazzo Immagine chiesa san francesco deruta Sony videocamere digitali Occhiali sole donna Shemale movie gallerie Sunia sicilia Codici pokemon smeraldo gba Mega natural tit Disegni geco

Negative Film

Printed Circuit Boards I start with a hand drawn schematic. The schematic is then prototyped on a breadboard (prototype board). Breadboarding provides a test platform for circuit designs. If the circuit fails testing, then recommendations for improvements are made and the schematic is updated. Once a circuit is thoroughly tested and proven reliable then the circuit is entered into a CAD package for electronic storing, editing and printing.

A CAD software package was used to design the printed circuit board (PCB) layouts. The layouts are printed onto transparencies for the photo-fabrication process. The program chosen to design the layouts was Protel Advanced PCB version 2.8. The layouts are designed manually from the schematics. Protel allows the creation of a custom library of components. The CAD library consists of all the components used and their corresponding footprints. Each component in a schematic has a footprint. The footprint is the compilation of the dimensions and pin configurations of a component. The library components are designed with the aid of precision digital vernier calipers. Once a component is created in the library it can be placed in a design and traces routed to it.

The PCBs were made using a positive photo-fabrication process. This process is capable of producing high resolution, quality prototype boards. The PCB material used is a presensitized copper clad board. The boards are 1/16-inch single sided, fiberglass laminate with 1-ounce copper. Before exposing the boards I cut them to the desired dimentions.

Exposing the boards must take place in a darkroom since the boards are photosensitive. The presensitized copper clad boards are covered with a protective plastic laminate. Beneath the protective laminate is the resist coating over the copper. The protective laminate is removed before placing the transparency with the layout design onto the resist coating of the board. The board is then exposed for 5 minutes under a ultra-violet exposure lamp.

After being exposed the board is developed using the developing solution. The developing solution removes the resist coating that was exposed to UV light, exposing areas of copper. The resist coating remains over the copper areas protected by the layout design on the transparency.

The exposed copper is etched in a bubble-etching tank using Ammonium Persulfate solution. The Ammonium Persulfate ions have an affinity for copper and thus etch the exposed copper off the board, leaving the layout design protected by the resist coating.

The components used for the design are t 1000 hru-hole and thus require holes to be drilled in the PCB for placement. The holes are drilled using carbide bits. Carbide bits are required to drill through the fiberglass laminate. Regular bits are not durable enough and wear out too quickly.

Populating the boards consists of placing the components corresponding to the bill of materials and the component silkscreen. The bill of materials provides the components part numbers and details. The silkscreen printout from the layout design provides the component location on the board.

The components are soldered on starting with jumper wires, resistors and working up to ICs and larger components.

External Links

• Yet another PCB guide