Alternative ways to use a test pen
In addition to being able to determine whether an object is charged, the voltage test pen also has the following uses:
(1) It can be used to conduct low-voltage phase verification and measure whether any conductors 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 the two wires to be tested. If the two test pens glow very brightly, the two wires are different. phase; otherwise, it is in the same phase. It is judged by using the principle that the voltage difference between the two poles of the neon bulb in the electric test pen is proportional to the intensity of its luminescence.
(2) Can be used to distinguish alternating current and direct current. When testing with a test pen, if both poles in the neon bulb of the test pen light up, it is alternating current; if only one of the two poles emits light, it is direct current.
(3) Can determine the positive and negative poles of DC. Connect the test pen to the DC circuit to test. The bright pole of the neon bulb is the negative pole, and the non-lit pole is the positive pole.
(4) Can be used to determine whether DC is grounded. In a DC system insulated from 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 shines, it means there is a grounding phenomenon. If it shines like at the tip of the pen, it means the positive electrode is grounded. If it lights up at the end of your finger, it means the negative pole is grounded. However, it must be pointed out that in a DC system with a ground monitoring relay, this method cannot be used to determine whether a ground fault occurs in the DC system.
Why does the test pen not glow when measuring the zero line?
Not only does the current flow through, but it is also equal to the current in the live wire, because the neutral wire is connected in series with the live wire and electrical appliances, and the current is equal everywhere in the series circuit. If you don't believe it, just test it with an ammeter. As for why it cannot be measured with a test pen, it is very simple, because the test pen is used to distinguish the live wire and the neutral wire, or to determine whether the conductor is connected to the live wire, and cannot determine whether there is current. When the metal body of the tip of the test pen contacts the live wire or a conductor connected to the live wire, a loop is formed from the live wire through the test pen, the human body, and the earth. Because there is a 220V voltage between the live wire and the earth, a weak current flows from the live wire through the test pen and the human body. It flows to the earth, and the neon tube of the electric test pen glows, but it is not the same as the current in the live wire. When the metal tip of the test pen touches the neutral line, there is no voltage between the neutral line and the ground, so no current flows through the test pen, and the neon tube of the test pen does not emit light.
