A question about PC boards?

Question

How do people know how to make them? like how do they know where to put every little transistor, diode, ic chip, capacitors, etc...
and how do they know what it is going to do,what will the output be? what if it needs an input, where to you attatch that?where do you attach the power source?.............

Answer 1

It takes a lot of schooling and experience to lay out a PC board for a computer. Some of it is hands-on learning, some of it may be intuition. It's a lot of work. You not only have to plan where everything goes physically, but also make sure that signals don't interfere with each other as they are routed to different parts of the board. A lot of it these days is computer aided design. Todays computer does the design for the next generation computer.

Answer 2

You design it! I was initially self-taught, by looking at existing designs, and modifying them. Taking things apart, fixing them. I eventually went to school, and made a career out of it.

First you decide what you want to make. Then either find an existing schematic, or design your own. Either way, you should breadboard the circuit first to make sure it works. Breadboarding is a tool, where you can plug in the components and wire it together without a PC board. Once you have a schematic, you lay it out so that you can easily make all the connections.

The actual process of making the boards can be done a couple of ways. The way I'm going to describe is with a laser printer, and etching chemicals. You use a layout program, many of which are free on the internet, and draw out the traces. Then you laser print the image on to a piece of paper, and use a hot iron, to transfer the image to a PC board coated with copper on one side. The toner covers the areas of the copper that you do not want to etch off. You use a special pen to clean up some of the traces where the toner did not transfer perfectly.

Once you get the design right, you pour the etching chemicals over the board, and the copper gets removed where it is exposed. You remove the board from the bath, and rinse it off. Now all you do is clean off the toner, and you have a PC board.

Power sources can be internal with a power cord, or with a wall wart. Electronics houses sell boxes, where you can house your prototybe board, and have switches, lights, displays, and whatever