The non-contact voltage tester detects the presence of voltage in an insulated wiring and at a short distance from it. Voltage detection is indicated by a red LED, a sound signal, and an indication on the LCD screen. The tester exploits the phenomenon of electromagnetic induction. The closer it is to the voltage source, the higher the frequency of the indications. When activated, the tester operates in low sensitivity mode, where the frequency increases upon contact with the wire. In high sensitivity mode, the frequency increases about 1 cm from the wire. The tester also allows for "non-contact" detection of a break in a live electrical wire. At the break point, the tester will stop indicating the presence of voltage.