he tester pen is probably the most essential kind of electrical tools, and the electroscope is most commonly used to measure whether there is voltage in the line. But in fact, its function is not simple, there are many functions.
The Test pen to measure whether there is voltage in the line
This is one of the most commonly used functions of a test pen, which is to hold the pen in the correct position and touch the conductor with the tip of the pen. If the light of the electric pen is on, it proves that there is voltage in the circuit, and if the light is not on, it proves that there is no voltage in the circuit. However, in actual use, it should be noted that it is not possible to judge whether the circuit is normal or not by the light or non-light of the electric pen alone. For example, both the live wire and the wrongly connected neutral wire can light up the electric pen, but the former is a normal phenomenon, while the latter is a fault.
