A jumper wire is a short insulated wire with bare (stripped of insulation) ends. You use jumper wires, such as the one shown in the following figure, to connect two points in a breadboard circuit. Even if you have a set of precut jumper wires, chances are you'll need to make a jumper wire of a specific length for a circuit or two.
Making a jumper wire isn't that hard, as long as you have the right wire, tools, and a little patience.
You start with a reel (or long piece) of insulated wire that is thick enough — but not too thick — to fit into the contact holes of your breadboard. The gauge (pronounced "gage") of a wire is a measure of its diameter. Look for 20- or 22-gauge wire. In North America, the gauge is often labeled AWG (for American wire gauge).
You also need a wire cutter and a wire stripper, or one tool that does both jobs, as well as needle-nose pliers. You'll find it much easier to make jumper wires if your wire stripper has a gauge-selection dial or several cutting notches labeled for various gauges. Gauged devices allow you to strip insulation without worrying about cutting the wire underneath the insulation.
If you use a generic wire stripper, you have to be very careful not to nick (accidentally cut into) the wire when you're stripping off the insulation. Nicks weaken the wire, and a weak wire can get stuck inside a breadboard hole and ruin your whole day.
To make your own jumper wire, follow these steps:
Cut the wire to the length you need, using a wire-cutting tool.
If you need, say, a 1-inch jumper wire, cut a length of wire that is at least 1-3/4 inches long, so you leave room to strip some insulation off each end. It's better to cut a longer length of wire and trim it down if you need to than to cut a shorter length of wire and find that it's too short for your circuit.
Strip off about 1/4- to 1/3-inch of insulation from each end.
If you use a gauged wire stripper, follow these steps:
Dial the gauge to 20 or 22 (depending on what gauge your wire is) or locate the notch that is labeled 20 or 22.
With the jaws of the wire stripper open, place the wire in the appropriate notch of the wire stripper, so that roughly ¼- to 1/3-inch of the wire extends past the wire stripper.
Firmly grip the wire stripper — as if you're trying to cut through the wire — while twisting and pulling the wire through the stripping tool. The insulation should come off but the wire should remain intact.
If you use a generic wire stripper, follow these steps:
Place the end of the wire into the cutting blades of the wire stripper, so that roughly 1/4- to 1/3-inch of the wire extends past the wire stripper.
Grip the wire stripper just enough to begin cutting through the insulation. (If you grip it too tightly, you will nick or cut through the wire. If you don't grip it tightly enough, you won't cut through the insulation at all.)
Release your grip on the wire stripper, rotate the wire a quarter turn, and then grip the wire stripper again with just enough pressure to begin cutting through the insulation.
Rotate and repeat steps b and c two or three more times, until you have nicked the insulation all the way around the wire.
Grip the wire stripper — but not too tightly — around the nicked insulation while pulling on the other end of the wire to force the insulation off.
Bend the exposed ends of wire at a right (90-degree) angle.
Use your needle-nose pliers to do this.
With a little practice, you'll become an expert in making jumper wires!
