Electronic Project Plan Step 4: Construct Your Circuit
Once you’ve prototyped your electronic circuit and you are satisfied with its operation, you can build a permanent version of the circuit. Although there are several ways to do that, the most common is to construct the circuit on a printed circuit board, also called a PCB.
Note that assembling a circuit on a PCB requires that you know how to solder.
Understand how printed circuit boards work
A printed circuit board is made from a layer of insulating material such as plastic or some similar material. Copper circuit paths are bonded to one side of the board. The circuit paths consist of traces, which are like the wires that connect components, and pads, which are small circles of copper that the component leads can be soldered to.
There are two basic styles of printed circuit boards available:
Through-hole: A PCB in which the copper circuits are on one side of the board and the components are installed on the opposite side. In a through-hole PCB, small holes (usually 1/16″ in diameter) are drilled through the board at the center of the copper pads.
Components are mounted to the blank side of the board by passing their leads through the holes and soldering the leads to the copper pads on the other side of the board. Once the solder joint is completed, any excess wire lead is trimmed away.
Surface-mount: A PCB in which the components are installed on the same side of the board as the copper circuits. No holes are drilled.
Surface-mount PCBs are easier for large-scale automated circuit assembly. However, they’re much more difficult to work with as a hobbyist because the components tend to be smaller and the leads are closer together.
Use a preprinted PCB for your electronic project
The easiest way to work with printed circuit boards is to purchase a preprinted board from RadioShack or another electronics parts supplier. RadioShack carries several different preprinted circuit boards in their stores. You can find an even greater variety of preprinted PCBs if you shop online distributors such as Hobby Engineering, Jameco Electronics, or All Electronics.
As you can see, preprinted PCBs come in a wide variety of shapes and sizes. The most useful, from a hobbyist’s point of view, are the ones that mimic the terminal-strip and bus-strip layout of a solderless breadboard. With a preprinted PCB that has a breadboard layout, you can transfer your breadboard prototype circuit to the PCB without having to come up with an entirely new layout.
Some preprinted circuit boards have layouts that are similar to standard breadboard layouts, but not identical. So check carefully before you build; you may have to make minor adjustments to your circuit layout to accommodate the PCB you’re using.
If necessary, you can cut a larger PCB to a smaller size. One way to cut a PCB is to score it on both sides with a heavy-duty utility knife, and then snap it at the score. Another way is to cut it with a rotary tool such as a Dremel.