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First, what is a PCB? It is a Printed Circuit Board. Look to the left of this web page and you'll see an image of a small PCB as part of a group of PCBs. Here is another example of one: Have you ever looked inside your computer, a radio or a telephone? The printed circuit boards inside it are the flat, thin, square, usually green fiberglass slabs that have electrical components attached. Harder to see are copper traces running underneath the green covering. You would have to try different angles of light to see them. These are wires that are "printed" on the fiberglass slab. They connect the electrical components, thus forming circuits. Thus the name "printed circuit board." A company that manufactures electronic products has a cycle of production to go from concept to end user or customer. It could be thought of like this: Marketing - Sales - Product Concept - Engineering & Design - Design for Manufacturing - Manufacturing - Assembly - Packaging - Distribution. The Design for Manufacturing step is where a PCB designer makes his contribution to that portion of the product that involves electronic circuits. For that part of the product, an electrical engineer has done the engineering, or circuit design in the step just before this. He has produced, among other sub-products, a diagram of the functionality of the circuit. This diagram is called a "schematic." It contains symbols connected by lines. For example, a zig-zag line is used to represent a resistor, a type of electrical component that reduces the voltage of a current that passes through it. The little zig-zag line does not even resemble what a resistor looks like, it simply symbolizes the function of a resistor, that it sort of "slows down" the current. A schematic diagram is composed of a variety of such symbols, not one of which looks like the component which it represents. In order to manufacture a printed circuit board, it is necessary to take the design from the functional diagram or schematic and change it into a form of artwork that makes the pattern of the components and wires, which is used in photographic imaging techniques to manufacture the PCB. The PCB designer is the person who creates the artwork for that purpose. The artwork is a lot like the plates used in printing, it forms the pattern that is "printed" into the PCB. The process is only analogous to printing. Technically it is quite different. To carry the analogy to printing a bit farther, let's use the printing of a book as a metaphor for production of an electronic device. The author of the book is the electronics design engineer or "double-E" or electrical engineer. The typesetter is the "layout guy" or PCB designer. So there you have it. © 2002-2008 John W. Childers. All Rights Reserved. |
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