How to test whether there is electricity in electroprobe?

The electric pen is a tool to detect whether there is electricity in the circuit, which is usually used to detect the current in the AC circuit. Let me talk about the method of testing whether there is electricity in the circuit with an electric pen: 1. Insert the electric pen into the power socket or contact with the tested wire; 2. If the light is on, it sounds, indicating that this part of the wire is transmitting alternating current; 3. If the light is off or there is no sound, it means that this part of the wire is not transmitting alternating current. It should be noted that the electric pen can only detect the current in the AC circuit, so it cannot be used to test the DC circuit. In addition, when conducting any form of electrical test, please follow the correct safety operation procedures, such as disconnecting the power supply system of the corresponding equipment and wearing appropriate safety equipment.