The voltage measuring pen can not only judge whether the object is charged, but also have the following uses:
1) It can be used for low-voltage nuclear phase measurement to measure whether any wires in the line are in phase or out of phase. The specific method is: stand on an object insulated from the earth, hold a test pen in each hand, and then test on the two wires to be tested. If the two test pencils glow brightly, the two wires are different. On the contrary, it is in the same phase, which is judged by the principle that the voltage difference between the two poles of the neon bulb in the test pen is proportional to its luminous intensity.
2) It can be used to distinguish between alternating current and direct current. When testing with a test pen, if both poles in the neon bulb of the test pen glow, it is alternating current; if only one of the two poles glows, it is direct current.
3) It can judge the positive and negative poles of direct current. Connect the test pen to the DC circuit to test, the neon bulb that glows is the negative pole, and the non-lighting pole is the positive pole.
4) It can be used to judge whether the DC is grounded. In a DC system insulated to the ground, you can stand on the ground and use a test pen to contact the positive or negative pole in the DC system. 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, and if the neon bulb is bright, 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.
Test pen to determine whether DC is grounded
If the zero line is broken, points A and B will be red when measured with a test pen, and the live line will reach point B through the electrical appliance, so point B will be red, and point C will not be red when it is the zero line. So use an electric pen to test and find that the socket is on fire and the zero line is red, and you can immediately think that the zero line is broken, or the rose of the terminal post is loose, or the zero line fuse of the knife switch is blown, or the mouse is biting .
