FIGURE 3-8: A soldering iron with a stand.
Multimeter
In Chapter 2 of this minibook, you learn that you can measure voltage with a voltmeter. You can also use meters to measure many other quantities that are important in electronics. Besides voltage, the two most common measurements you’ll need to make are current and resistance.
Rather than use three different meters to take these measurements, it’s common to use a single instrument called a multimeter. Figure 3-9 shows a typical multimeter purchased from RadioShack for about $20.
FIGURE 3-9: An inexpensive multimeter.
Solderless breadboard
A solderless breadboard — usually just called a breadboard — is a must for experimenting with circuit layouts. A breadboard is a board that has holes in which you can insert either wires or electronic components such as resistors, capacitors, transistors, and so on to create a complete electronic circuit without any soldering. When you’re finished with the circuit, you can take it apart, and then reuse the breadboard and the wires and components to create a completely different circuit.
Figure 3-10 shows a typical breadboard, this one purchased from RadioShack for about $20. You can purchase less expensive breadboards that are smaller, but this one (a little bigger than 7 x 4 inches) is large enough for all the circuits presented in this book.
FIGURE 3-10: A solderless breadboard.
What makes breadboards so useful is that the holes in the board are actually solderless connectors that are internally connected to one another in a specific, well-understood pattern. Once you get the hang of working with a breadboard, you’ll have no trouble understanding how it works.
Throughout the course of this book, I show you how to create dozens of different circuits on a breadboard. As a result, you’ll want to invest in at least one. I suggest you get one similar to the one shown in Figure 3-10, plus one or two other, smaller breadboards. That way, you won’t always have to take one circuit apart to build another.
You can learn more about working with solderless breadboards in Chapter 6 of this minibook.
Wire
One of the most important items to have on hand in your lab is wire, which is simply a length of a conductor, usually made out of copper but sometimes made of aluminum or some other metal. The conductor is usually covered with an outer layer of insulation. In most wire, the insulation is made of polyethylene, which is the same stuff used to make plastic bags.
Wire comes in these two basic types:
Solid wire: Made from a single piece of metal
Stranded wire: Made of a bunch of smaller wires woven together
Figure 3-11 shows both types of wire with the insulation stripped back so you can see the difference.
FIGURE 3-11: Solid and stranded wire.
For most purposes in this book, you’ll want to work with solid wire because it’s easier to insert into breadboard holes and other types of terminal connections. Solid wire is also easier to solder. When you try to solder stranded wire, inevitably one of the tiny strands gets separated from the rest of the strands, which can create the potential for a short circuit.
On the other hand, stranded wire is more flexible than solid wire. If you bend a solid wire enough times, you’ll eventually break it. For this reason, wires that are frequently moved are usually stranded.
Wire comes in a variety of sizes, which are specified by the wire’s gauge, and is generally coiled in or on the packaging. Strangely, the larger the gauge number, the smaller the wire. For most electronics projects, you’ll want 20- or 22-gauge wire. You’ll need to use large wires (usually 14 or 16 gauge) when working with household electrical power.
Finally, you may have noticed that the insulation around a wire comes in different colors. The color doesn’t have any effect on how the wire performs, but it’s common to use different colors to indicate the purpose of the wire. For example, in DC circuits it’s common to use red wire for positive voltage connections and black wire for negative connections.
To get started, I suggest you purchase a variety of wires — at least four rolls: 20-gauge solid, 20-gauge stranded, 22-gauge solid, and 22-gauge stranded. If you can find an assortment of colors, all the better.
Batteries
Don’t forget the batteries! Most of the circuits covered in this book use either AA or 9-volt batteries, so you’ll want to stock up.
If you want, you can use rechargeable batteries. They cost more initially, but you don’t have to replace them when they lose their charge. If you use rechargeables, you’ll also need a battery charger.
To connect the batteries to the circuits, you’ll want to get several AA battery holders. Get one that holds two batteries and another that holds four. You should also get a couple of 9-volt battery clips. These holders and clips are shown in Figure 3-13.
FIGURE 3-12: Jumper wires for working with a solderless breadboard.
FIGURE 3-13: Battery holders will help deliver power to your circuits.
Other things to stock up on
Besides all the stuff I’ve listed so far, here are a few other items you may need from time to time:
Electrical tape: Get a roll or two of plain black electrician’s tape. You’ll use it mostly to wrap around temporary connections to hold them together and keep them from shorting out. Do yourself a favor, and don’t waste time with cheap electrical tape. There’s a huge difference in quality. In my opinion, far and away the best electrical tape is Scotch Super 33+ Vinyl Electrical Tape. It’s about twice as expensive as bargain-basement tape, but you won’t regret spending a few extra dollars.
Compressed air: A small can of compressed air can come in handy to blow dust off an old circuit board or component.
Cable ties: Also called zip