You hear continuous chirping and see a series of flashes confirming that the tester has detected the voltage. This type of voltage tester allows you to test voltage without having to open or splice wires. This tool can also be used to dim the basement in situations where the light does not work, a small but helpful feature as it is the only model we have tested.

In fact, the mere presence of an electric field can trigger this type of voltage tester. Non-contact voltage testers work by measuring a small amount of current coupled to the circuit between the tester and ground. Since they are light, they can detect this current without direct contact.

A contactless tester is a device which allows the user to check the voltage of a variety of electrical appliances without touching wires or parts. The functioning of these devices is based on the use of capacitor couplings to detect electric fields. The built-in sensors at the top of the tester detect the presence of voltage without touching the conductor, socket or power cable.

Volt sticks are designed for a specific purpose: to detect the presence of AC voltage. The electric fields connected to the AC voltage are present in the current conductor, and the reason for this is the requirement of direct contact with the conductor. Another reason is that electric fields have to build up and collapse in order to induce a current in the volt rod circuit, which happens with alternating voltages.

If you refer to the capacitors in the video above, you can see that the current flows at an AC voltage. With a DC voltage, the electric field must build up and remain in one direction until a current is induced in the voltage stick circuit, and since there is no volt stick in the circuit it does not indicate the presence of a DC voltage. This is the reason why testers do not work with DC capacitors and why transformers do not work with DC voltage.

A few ticker markers, including the Southwire Dual Range non-contact voltage tester can detect two voltage ranges. The higher voltage range is the default, while the lower voltage range (tension range) at the upper end is kept at 1,000 V. Most voltage testers do not register voltages below, giving Southwire a significant advantage over simpler models.

Electrical testers are a good value option with impressive IP67 water resistance. Mid-range models such as the SouthWire non-contact voltage tester are designed to withstand the elements. If you need an outdoor quality tester, you will appreciate the IP67 waterproof housing of these pins.

The Small Non-Contact Voltage Tester (NCVT) is ideal for NCVT electricians working with HVAC, ventilation and air conditioning systems (HVAC). Not only is it the most reliable model in the price range of non-contact voltage testers, but also has the new Voltbeat technology that enables self-testing. When something goes wrong the problem can be detected by the sensor or from a device such as a nearby voltmeter or oscilloscope.