One should be very careful when working with electronic machinery or power grid, because improper behaviour and incomplete safety measures can lead to damaging your equipment, injury or even death. In case a malfunction occurs on a power grid or a gadget breaks down a specialist is required to analyze and repair the equipment. Voltage detectors have a simple function of indicating whether there’s electricity running through a wire or a device. Such gadgets give visual and/or audio signal if electric current is detected. There are three types of such detectors. The first has two leads, one of them is attached to a wire and the other one - to the grounding connection. The second type has only one connection, and it relies on the current that passes through a person using such device. It’s smaller and cheaper, but is not as safe as other types of detectors. The third type is a non-contact detector, it uses electric fields to detect the flow of electricity.