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Electronics for dummies - McComb G.

McComb G., Boes E. Electronics for dummies - Wiley publishing, 2005. - 433 p.
ISBN: 0-7645-7660-7
Download (direct link): electronicsfordummies2005.pdf
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projects behave erratically or unpredictably if you don't build them by using a printed circuit board and solder. You really need to be aware of this fact if you're working with RF (radio frequency) circuits, such as radio receivers and transmitters, digital circuits that use signals that change at a very fast rate (on the order of a couple of million Hertz), and more sensitive timing circuits that rely on exact component values. Solderless breadboards have a tendency to change the characteristics of some components, most notably capacitors and inductors; these variations can change the way a circuit behaves.
If you're building a radio or other circuit that stray capacitance can affect, you may have to forego the step of first building the circuit on a solderless breadboard. You may have better luck with the performance of the circuit by going straight to a solder breadboard or another type of soldering board, which we describe in the section "Prototyping with Pre-Drilled Perf Boards."
Leave space at the corners of the board so that you can drill mounting holes. You use these holes to secure the board inside whatever enclosure your project provides (such as the chassis of a robot). Alternatively, you can secure the board to a frame or within an enclosure by using double-sided foam tape. The tape cushions the board and prevents breakage, and the thickness of the foam prevents the underside of the board from actually touching the chassis.
Solder breadboards have one main disadvantage: They donít use space very efficiently. Unless you cram the components onto the board, the breadboard limits you to building circuits with only two or four integrated circuits and a handful of discrete components. In time, you can figure out how to conserve space and make good use of the real estate on a solder board.
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Chapter 11: Creating Your Own Breadboard Circuit 245
Prototyping with Pre-Drilled Perf Boards
Solder breadboards arenít the only kind of general-purpose circuit board that you can use for your projects. You have another option in a pre-drilled perf board with copper traces for wiring. These boards go by many names, such as a grid board or a universal, general-purpose, or prototyping PC board. Perf boards come in a variety of sizes and styles. Figure 11-6 shows a few perf board styles. All styles are designed for you to use with ICs and other modern-day electronics components, which means the holes are spaced 0.100 inch apart.
You may find perf boards handy when you want a soldered circuit but donít want to go through the much more laborious process of making your own circuit board from scratch. One of the main ways that you use perf boards is to construct circuits by using wire wrapping (see the section ďGetting Wrapped Up in Wire Wrapping,Ē later in this chapter for more about this). If the board has pads and traces on it, and most do, you can solder components directly onto it. But you can use a perf board without any copper pads and traces when you use the wire wrapping method.
Figure 11-6:
A few sample perf boards, ready for you to clean them if necessary and add electronics components.
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246 Part V: A Plethora of Projects
You can choose the style of grid board based on the type of circuit that youíre building. Some grid layouts suit certain applications better than others. Personally, we prefer the plain universal PC board with interleaved busses, as we think they are easier to use. (You donít ride the buss on a circuit board, you solder things to it. A buss in the electronics world is just a common connection point.) You tie components together on the universal PC board, using three- (or more) point contacts.
A buss runs throughout the circuit board so that you can easily attach components to it. Many perf boards have at least two busses, one for power and one for ground. The busses run up and down the board, as you can see in Figure 11-7. This layout works ideally for circuits that use many integrated circuits. Alternating the busses for the power supply and ground also helps to reduce undesirable inductive and capacitive effects.
You use the perf board just as you use a solder breadboard. After cleaning the board so that the copper pads and traces are bright and shiny, plug the components into the board and solder them into place. Use insulated wire to connect components that arenít adjacent to one another.
Figure 11-7:
Several busses run up and down this perf board.
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Chapter 11: Creating Your Own Breadboard Circuit 247
Making circuit boards with plug-'n'-play ICs
You may want to consider this idea when you build circuit boards that include integrated circuits: Instead of soldering the IC directly onto the board, use an IC socket. You solder the socket onto the board, and then, when you're done soldering, you plug in the IC and hit the switch.
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