Function 1: 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.
Function 2: Measure the in-phase or out-of-phase of the phase line
Circuits that do not distinguish between wire colors are definitely a headache when repairing. Single-phase circuits are okay, but if you encounter three-phase circuits, it's really a big head! However, the electric pen has a magical function that can easily help you measure the in-phase or out-of-phase of phase lines. When measuring, hold an electric pen in each hand and stand on an insulating object. Touch the two electric pens to the two wires at the same time. If the brightness of the two electric pens is low, it means that the two wires measured at this time are in phase (both phase wires). If the brightness of the two pens is high, it means that the two lines measured at this time are out of phase (one phase line and one neutral line). In this way, three phase wires and one neutral wire in a three-phase circuit can be quickly screened out.
Function 3: Distinguish between alternating current and direct current
The first is to distinguish from the brightness. The brightness of the electric pen when measuring the alternating current is significantly higher than that of the direct current. The second is to distinguish from the position of the brightness of the electric pen. The light of the electric pen, called the neon tube, is in the shape of a long strip. When measuring alternating current, the entire neon tube glows; when measuring direct current, only one end of the neon tube glows.
Function 4. Measure the positive and negative poles of direct current
When measuring direct current, only one end of the neon tube lights up. At this time, the positive and negative poles of the power supply can be judged by the position where the neon tube emits light. When measuring the positive pole of the power supply, the end of the neon tube close to the pen tip will light up; when measuring the negative pole of the power supply, the end of the neon tube farther away from the pen tip will light up.
