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Static electricity — more properly called electrostatic charge — results when electric charges (that is, voltage) builds up in the absence of a circuit that allows current to flow. Your own body is frequently the carrier of static charge, which can be created by a variety of causes. The most common is friction that results from simple things such as walking across a carpet. Your clothes can also pick up static charge, and usually do when you toss them around in a clothes dryer.

Static charge accumulated in your body usually discharges itself over time. However, if you touch a conductor — such as a brass doorknob — while you’re charged up, the charge will dissipate itself quickly in an annoying shock.

If the conductor happens to be a sensitive electronic component such as a transistor or an integrated circuit rather than a brass doorknob, the discharge can be more than annoying; it can fry the innards of the component, rendering it useless for your projects. For this reason, it’s wise to protect your stuff from static discharge when you work on your electronic projects. The easiest way to do that is to make sure you’re properly discharged before you start your work. If you have a metal workbench or a large metal tool such as a drill press or grinder near your workbench, simply reach out and touch it after you’ve settled in to your seat and before you begin your work.

A more reliable way to protect your gear from static discharge is to wear a special antistatic wristband on one wrist, as shown in Figure 4-2. Wear the wristband tightly so that it’s in good solid contact with your skin all the way around your wrist. Then, plug the alligator clip into a metal surface such as your workbench frame or that nearby drill press.

FIGURE 4-2: An antistatic wristband.

For best results, the alligator clip on your antistatic wristband should be connected to a proper earth ground. To create a proper earth ground, clamp a long length of wire to a metal water pipe. The wire should be long enough to reach from the pipe to your workbench. Carefully route the wire from the pipe to your workbench, strip off an inch or so of insulation, and staple or clamp the wire to the workbench, leaving the stripped end free so you can attach the alligator clip from your antistatic wristband to it. (Note that this technique works only if the building uses metal pipes throughout. If the building uses plastic pipe, the water-pipe won’t provide a proper ground.)

An often-recommended way to connect the wristband to an earth ground is to connect it to the ground receptacle of a properly grounded electrical outlet. I’m definitely not a fan of this method, as the key to its operation lies in the term “properly grounded electrical outlet.” All it takes is one stupid wiring mistake, or one wire shaken loose by a sonic boom or a mild earthquake, and suddenly that ground wire might not be a ground wire anymore — it might be energized. Call me paranoid if you wish, but there’s no way I can recommend strapping a conductor around your wrist and then plugging it into an electrical outlet.