A non-contact Voltage Tester is an electrical tester that detects the presence of voltage. This instrument plays a key role in troubleshooting or working on a failed asset. The non-contact voltage detector is the handiest tool.
The other names of this tester are:
Non-contact voltage tester works by sensing a small amount of current capacitively coupled from the live circuit to the tester and back to the ground. These testers light up when they detect current without needing to make direct contact.