Electrical Testers

What are Electrical Testers?

Electrical testers are a family of products that can detect the presence of voltage and/or current quickly and easily. Electrical testers are portable and ergonomic, allowing the user to safely hold the instrument near the source of electricity for testing. Electrical testers can detect AC only, DC only, or both AC and DC signals. Some testers can also provide
continuity and phase tests.

Contact and Non-Contact Electrical Testers

There are two types of testers: Contact and Non-Contact. Contact testers, as the name implies, have probes that must physically come in contact with the signal under test in order to make a measurement. Non-contact devices detect the electrical signal through magnetic induction and therefore do not need a physical connection to make a measurement.

AC and DC Electrical Testers

The most common testers measure AC signals. AC (alternating current) is the power that is provided by utility companies to homes, offi ces, and manufacturing plants. AC signals are present at breaker panels, wall outlets, switches, light fi xtures, etc. DC testers (direct current) are geared toward the measurement of low voltage signals associated with battery powered circuits.

How are Electrical Testers used?

Electrical Testers detect the presence of voltage or current at an outlet, power strip, light fi xture, wall switch, or any location where electricity may be present. The user places the tester near (in the case of a non-contact tester) or in touch with (in the case of a contact tester) an electrical circuit. The tester may provide the measurement results audibly, visually, or by both means. Audible detection is usually by way of chirping tones that grow louder and more insistent as the electricity amount increases. Visual alerts can be simple LED lights or full digital readouts with bargraphs.

A note about sensitivity adjustments

Many Electrical Testers include a sensitivity adjustment. Such an adjustment allows the user to more accurately detect the presence of electricity by mitigating the possibility of false detection. False detection can occur when there is a large amount of static electricity present that triggers the Electrical Tester. This can confuse the user as to the presence
of electricity in the circuit under test. By adjusting the tester’s sensitivity, the false triggering can be minimized.