Principles and Uses of Electricity Detector Pen
Electricity stylus is one of the tools often used by the majority of electricians to determine whether the object is electrically charged. Its internal structure is a light bulb with two electrodes, the bubble filled with neon gas, commonly known as neon bubble, one of its pole to the tip of the pen, the other pole in series with a high resistance to the other end of the pen. When the voltage between the two poles of the neon bubble reaches a certain value, the two poles will produce a glow between the two poles, the intensity of the glow is proportional to the voltage between the two poles. When the voltage of the charged body to ground is greater than the glow voltage of the neon bubble started, and the tip of the pen will be in contact with it, the other end of the pen is grounded through the human body, so the pen will glow. The role of resistance in the stylus is used to limit the current flowing through the body to avoid danger.
In addition to determining whether an object is electrically charged, the stylus has several other uses:
(1) can be used for low-voltage phase verification, measuring the line between any conductors whether the same phase or different phase. Specific method is: standing in an object insulated from the earth, hands holding a stylus, and then in the two wires to be tested on the test, if the two stylus luminous is very bright, the two wires for the phase; Conversely, it is the same phase, it is the use of neon bubbles in the stylus the difference in voltage between the poles of the neon bubble and its luminous strength is directly proportional to the principle of discrimination.
(2) can be used to distinguish between alternating current and direct current. In the test with the stylus, if the stylus neon bubble in the two poles are glowing, is the alternating current; if the two poles of only one pole is glowing, it is direct current.
(3) You can determine the positive and negative poles of direct current. Will be connected to the stylus in the DC circuit test, neon bubble light up the pole is the negative pole, does not light up the pole is positive.
(4) can be used to determine whether the DC ground. Insulated to ground in the DC system, can stand on the ground with a stylus contact DC system in the positive or negative pole, if the stylus neon bubble does not light up, there is no grounding phenomenon. If the neon bubble is bright, it shows that there is a grounding phenomenon, and its bright such as the tip of the pen, then the positive pole is grounded. If the light is at the end of the finger, it is negative grounding. However, it must be pointed out that in the DC system with a ground monitoring relay, this method can not be used to determine whether the DC system is grounded.
