Photoetching

From OpenCircuits
Revision as of 14:34, 15 October 2007 by 160.109.98.52 (talk)
Jump to navigation Jump to search

trieste londra arc 4170 ix ati radeon 9250 128 solo singole sesso faretto a tenuta stagna il ragazzo che sapeva amare destruction derby www virilio it agenzia immobiliare asolo voli otranto frigorifero 12 w tendine parasole lubbock percy hard disk 160 gb serialata toshiba portatile 17 pollici letteratura per ragazzi altoparlante portatile quella fantastica pazza ferrovia dead man walking condannato a morte hedberg tor preventivi online assicurazione latin chart mixer yamaha codici telecomando tv video michele viet copy ps2 games navigatore satellitare garmin quest rsmmc dual voltage per cellulari nokia enya angeles secret of sahara la guerrillera humax digitale terrestre 5000 marcia militare turca hifi jvc mercedes 260 e limousine paola e chiara nude searchwin it i racconti di farfallina hp 1310 aumenta la distribuzione mondiale delle console sony sintomi del melanoma della pelle tod browning designer whey annuncio calabria retro volpin padova aladim il piu bel giovo rossana casale ospedale cava de tirreni inviti matrimonio elicotteri da guerra imprese estere abbigliamento uomo jeans diesel rgazze escort www alitalia virtual com treece henry gps su compact flash consolato italia a cuba hubble edwin powell auto noleggio livigno cambogia express batteria non originale the reasno procter gamble notti inquiete pixma 4000 asciugabiancheria hoover www dive it le date di mega man anniversary collection it gbm gli stessi sguardi don t tell my acer notebook dj lasa giulia cou tout roch zanzariera finestra contratto weekend immobile concorsi vfb moto modellismo scoppio cancion pasion de gavilanes yoshi tenaga laser colori 2400 dpi epson rx 420 sonda temperatura jvc d240 yamaha dgx sex2001 atlantis radeon 9600 g a del po corsi e ricorsi breast cancer www la disciplina la docimologia it hidden camera blu (lessico) pachabel canon think twice brathe easy blue midi juegos de gratis olivetti jp 883 ericsson r320s les etains du graal hannelore elsner franci blaskovic lg 9900 labirinto divertenti giochi gage cracked clientela pescara (fiume) holiou tettone video ddr2 512 mb kingston proliant ml370 i piu bei giochi ifa villas bavaro ecw aeron pre attrezzo palestra usato maron scuola edile jvc lettore dvd puma grit cat freecom fhd2 pro 80gb mobili anni 70 amd athlon fx55 tempo italia verbania sabato domenica trattori da giardino ritratto di un killer barry ryan eloise lesbo piss agriturismo terme di saturnia i raccomandati sigla champion league hp laserjet 9000 palmare typhoon gps lettore mp3 e radio fm ubbidire smart fortwo coup pure nude photos of sports dvd grieco data recovery recupero dati la marianna puntita juxian chitarra scudetto 4 le notti macchine sequestrate a firenze files seca kia sorento usati lebt dann der alte holzmichel noch ctb rudiano saintmoritz giuseppe venduto dai fratelli quelimane card del wresling cpa uomi piu ricchi al mondo foto cazzo come uccidere vostra moglie opel omega lotus touch me globus myo selen v ideo gratis mappa milano ricambi mini minor quattrocento colpi motorola 600 politiche del lavoro campania episodi orange county aspiraliquidi e solidi erika michelle le ali ai piedi snc eamon i dont want you back politicas de calidad en las empresas golf plus 20 tdi motorola v3 razr silver les brown terence hill supercop nike silver argento campolongu escort com kanye west czarne oczy mp3 simboli cartelli e segnali vip nude gallery ricetta novita fujitsu simens notebook estraibile sata smart roadster coupe appuntamento per una vendetta verbatim cdr super azo crystal 52x navtech e bello ave na donna dentro casa green day basket case trafficanti del piacere tha girl in the other room cover covercoat blue get down on it

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 thru-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