Читать книгу Electronics All-in-One For Dummies - Lowe Doug, Doug Lowe - Страница 84

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. Figure 6-13 shows a typical printed circuit board.

FIGURE 6-13: A printed circuit board.

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 inch 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. When 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. Thus, all the PCBs used in this book are of the through-hole variety.