About the Uses and Operating Methods of Voltage Tester Pens
① It can be used for low-voltage phase checking to determine whether any two wires in a circuit are in-phase or out-of-phase. The specific operation is as follows: stand on a large conductive object, hold one voltage tester pen in each hand, and then touch the two wires to be tested respectively. If both tester pens glow brightly, the two wires are out-of-phase; otherwise, they are in-phase. It judges based on the principle that the voltage difference between the two neon tubes inside the tester pen corresponds to the strength of their glow.
② It can be used to distinguish alternating current (AC) from direct current (DC). When testing with a voltage tester pen, if both electrodes of the neon bulb inside the tester pen light up, it is alternating current. If only one of the two electrodes lights up, it is direct current.
③ It can be used to judge the positive and negative poles of direct current. Connect the voltage tester pen to a DC circuit for testing. The electrode where the neon bulb lights up is the negative pole, and the non-lit electrode is the positive pole.
④ It can be used to check whether a DC system has a ground fault. For an insulated DC system, stand on the ground and touch the positive or negative pole of the DC system with the voltage tester pen. If the neon bulb glows, there is a ground fault. If it glows at the *, it means the positive pole is grounded; if it glows at the finger end, the negative pole is grounded. However, this method must not be used to judge grounding conditions in DC systems equipped with a grounding monitoring relay.
