What are the uses of a test pencil?

In addition to being able to measure whether an object is charged, the test pen also has the following purposes:

① It can measure whether any wires in the circuit are in phase or out of phase. The method is to stand on an object that is insulated from the ground, hold a test pen in each hand, and then test on the two wires to be tested. If the two test pens emit bright light, the two wires are out of phase, otherwise they are in phase.

② You can distinguish between alternating current and direct current. If both electrodes (at both ends of the neon tube) in the electric pen emit light during testing, it is an alternating current. If only one of the two poles emits light, it is direct current.

③ It can determine the positive and negative poles of direct current. When tested on a DC circuit, the bright pole of the neon tube is the negative pole, and the non bright pole is the positive pole.

④ Can determine whether the DC is grounded. In a DC system with insulation to ground, standing on the ground can be used to contact the positive or negative poles of the DC system with a test pen. If the neon tube of the test pen is not lit, there is no grounding phenomenon. If it lights up, it indicates the presence of grounding. It shines like at one end of the pen tip, indicating that the positive electrode is grounded. If it shines on one end of the finger, it is negative grounding. However, those with grounding monitoring relays are not subject to this restriction.