Photoetching
hoostabank mp3 incontri seri d amore i protagonisti della sai l ultima il gru ppo blue home let me out side alone la riviera http venus unive it if you come back la morte di enzo baldoni la maza il rinascimento jamie cullum impianti idraulici land rover 109 soft top honda sh jasmin com mx joss stonr liberamente livia leone drag high voltage remix loaded stage 1 incontriamoci jack lo squartatore immagini riccardo scamarcio lap dance strip tease roma jej czrne laeticia casta hino sport lisboa benfica lisa hall jonny mcgovern letras isabella baldassari hero enrique iglesias kejo toshiro jennifer paige spartiti les chevalier du ciel hewja lavori con perline movies celebrita loaded saturn la novela de pasion de gavilanes y sus jovanotti piove lapaloma immagini dell esecuzione di enzo baldoni in bank net lorena errera left me outside alone himno uefa champions indireu jaime hammer irene ferri jeden taki dzie letitia casta nuda i consigli di un pirla lowara i tutti i miei giorni la zitella jannacci l armando lupa di roma i m not giving u up la canzone dei gabbiani itinerario roma hopes and fears kaos meridionalis lazio calcio midi manuale beretta 7 65 itinerary ryanair com lima karine last thing of my mind la morena key of tps khris y angel kamassu kurnikova kai busk la maternite et le travail lolloscan http www biologia uniba it clbiologia los caminos da la vida vicentico lou x la usurpadora hascisc l hully gully java applet keane hopes and fears juliana delfino lo se kama sutra imnrc john olms foto hai la testa un po confusa la batidora de don omar lola ponce mp3 marcie funebre infotrafic historia de america antes de la conquist kelly munogue l antiquario giovanile lets get married holly wolloughby let s get started knight rieder locorotondo jimmorrison goodnight il primo furto inglesine vogliose laggio automobili incontri gay sesso lully bosa lu cardillo 24 grana istituti di catania haidichi il mago e la strega i want you bad hong nhung picture il cerca case piombino lg u81110 left qutside alone loredana ferro heat my heart guns an roses lurman java nokia hippo jamaba irmin into the west annie lennox he is my dj kazem hi fi sae il calendario sexi di paola perego del 2 l ultimo romantico midi i primi programmi della uri l esclusa pirandello riassunto lettera cara mamma labuonastella la cafetera seca keys hilary duff nude hedvika lettura veloce his constitutis rebus nactus idoneam lmagine legge n 432 del 19 11 98 laetitia songtext le tette di lollo ferrari inno dei bersaglieri kenny g havana remix lettori mp4 i film di tinto brass intenzioni matrimonio hay algo en ti de zion y lenox liberatoria modulo la luna ti portera fortuna let3 larice hhhjhh kelis trickme immagini cobra latinka i believe in a thing called love italmarket com julietavenegas il trovatore i rogers guarda larenga com lunezia 2004 il sesso i don t nknow why kaila ewell lobos lo starno percorso hanry morgan bravo club iscrizione infermieri in abruzzo il quotidiano della calabria haiducii musica la notte se ne va hir aj hir aj go korgis everybody s got to learn sometime immagini loghi di pesca hey joe hit mania dance champions 2003 left otside alone hotel mignon diano marina l inverno di antonio vivaldi ingrosso films in dvd hajrija gegaj la mano peluda kangoo 4x4 krypta 11 hikari no densetsu jane rivombrosa kings convenience lettere cinese kevin kline lamar jolie dairi katies holmes sexy kim sun ir la salute nello sport
This article is a stub. You can help Open Circuits by expanding 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.
