Other uses of the test pen

The most familiar tool for electricians is the electric pen, which is used to determine whether an object is charged.

In addition to judging whether the object is live, the electric tester has the following uses: 　 

(1) It can be used for low-voltage phase verification, measuring whether any wires in the circuit are in the same phase or out of phase. The specific method is: stand on an object insulated from the earth, hold a test pen with both hands, and then test on the two wires to be tested. If the two test pens are very bright, the two wires are different. On the contrary, it is the same phase. It is judged by the principle that the voltage difference between the two electrodes of the neon bulb in the electric tester is proportional to its luminous intensity. 

(2) It can be used to distinguish between alternating current and direct current. When testing with a tester pen, if both poles in the neon bulb of the tester pen emit light, it is an alternating current; if only one of the two poles is glowing, it is a direct current. 

(3) The positive and negative poles of the direct current can be judged. Connect the electric tester to the DC circuit for testing. The shining electrode of the neon bulb is the negative electrode, and the non-lighting electrode is the positive electrode. 

(4) It can be used to judge whether the DC is grounded. In the DC system insulated to the ground, you can stand on the ground and touch the positive or negative pole of the DC system with a test pen. If the neon bulb of the test pen does not light up, there is no grounding phenomenon. If the neon bulb is bright, it means that there is a grounding phenomenon. If it is bright on the tip of the pen, it means that the positive electrode is grounded. If it shines on the finger end, it is the negative ground. However, it must be pointed out that in a DC system with a grounding monitoring relay, this method cannot be used to determine whether the DC system is grounded.