Saturday, August 22, 2015

The Birth of a PCB

In many ways I am leaning to both appreciate and hate Proto-Board. I can see where it has it's uses but it sure is kind of hard to work with for a newbie like me on more complex circuits, lol and this is hardly what most would probably call a complex circuit. ;) This kind of thing always looks better on a nice printed PCB board and it makes putting the components onto the board a lot easier too, I realized this when I made the simple two LED flasher circuit that came in the electronics starter kit I bought on eBay as it had a simple small printed PCB board and soldering in the parts following along with the instructions was child's play compared to this ugly mess you see here (above left).

One has to admit that the printed PCB boards are so much nicer, cleaner and professional looking, even knowing where to solder your components onto the board is much easier to determine with all the tracks on the board clearly traced onto the board.

I have to give very special thanks Andrea lannaccone one of my Knight Rider friends on Face Book for doing this very awesome printed PCB for me. Andrea walked me through the simple process of how he creates these very nice printed PCB's.

The drawing of the circuit diagram can be done in applications like EAGLE, (left). Once you have your circuit figured out you then print your design onto a transparency.

Andrea shows the transparency here (left) with the 555 timer I.C. just dropped into it's correct orientation just to check for accuracy in the circuit design. Sometimes two transparencies may be required if there are any areas that may not be completely solid black or may have holes where the printer miss printed, can happen with transparent film from what I understand.

Next the transparency is placed over top of the Copper coated PCB board, some people use a picture frame with glass to hold the film firmly against the PCB. Andrea uses a product called "Presensibilzed" which is a PCB board with a special Photo resist ink printed over top of the copper coating on the PCB. The transparency will mask the areas of the board that are to be kept.

The PCB is them blasted with Black Light in a dark room for a certain amount of time. 
Next you have to wash off the excess Photoresist with a solution of water and Caustic Soda.
 The next stage is the Etching Bath which will remove all of the areas affected by the Black Light (lower left).

What comes out of the etching solution after all the unwanted Copper has been etched away is your final beautifully printed PCB board (lower right). From this point all that is needed to be done is drill in your holes with a fine drill bit for your components, solder them carefully into place and then you are done, out side of giving it a test run ;)