# Testing a Coil

Since an inductor is simply a wire coil, it can be tested for continuity in much the same way as a transformer is tested.

Visually inspect the wire for deterioration. If it shows signs of breakage or burned areas, it should be replaced. If the wire looks good, follow up with a conductivity test. Turn the system power off. Disconnect one lead to the coil (this might require a soldering iron) and connect one meter lead to each end of the coil. A null or low reading indicates continuity. A reading of high or infinite resistance indicates a lack of continuity. Replace the coil.

## Lesson Summary

The following points summarize the main elements of this lesson:

• Ohm's Law is the basic formula for power calculations.

• There are two types of power: alternating current (AC) and direct current (DC).

• A multimeter is used to measure volts, amps, continuity, and resistance.

• A computer technician should be familiar with the various electronic components found on a power-supply circuit board.

• In a new installation, a computer technician should never assume that the power supplied in the wall outlets is correct. Always test and be sure.

• Be careful with large electrolytic capacitors. They can store electrical charges and must be discharged before it is safe to work with them.

# Electrostatic Discharge (ESD)

This lesson discusses a phenomenon that can damage or ruin sensitive electronic equipment-electrostatic discharge (ESD), sometimes referred to as static electricity. Fortunately, it is one of the easiest things to protect against.

After this lesson, you will be able to:
• Define ESD (electrostatic discharge).

• Avoid ESD.

Estimated lesson time: 15 minutes