Discussion on the use of pencil

- Mar 22, 2018 -

Pencil In addition to the determination of the object is charged, there are several uses:

(1) can be used to carry out the Low-voltage nuclear phase, measuring the line between any of the wires are the same or different phase. The specific method is: Standing on an object with the Earth insulation, both hands holding a test electroprobe, and then tested on the two wire to be measured, if two pencil luminous very bright, then the two wires for the different phase; It is based on the principle that the voltage difference between the two poles of neon in pencil is proportional to its luminous strength.

(2) can be used to distinguish between alternating current and DC power. When tested with pencil, if two of the pencil neon light glows, it is alternating current, and if only one of the two poles is glowing, it is DC.

(3) The positive and negative polarity of direct current can be judged. The pencil is tested in the DC circuit, and the neon light is the anode, and the one that does not shine is the positive pole.

(4) can be used to determine whether DC grounding. In the ground-insulated DC system, can stand on the floor with pencil contact DC system of positive or negative, if pencil neon bubble is not bright, there is no grounding phenomenon. If the neon bulb shines, it indicates that there is a grounding phenomenon, its shiny as in the tip of the pen, the positive electrode grounding. If shiny at the finger end, the negative electrode is grounded. But it must be pointed out that in the DC system with grounding monitoring relays, this method cannot be used to determine whether the DC system is grounded.

Pencil is one of the most frequently used tools used by electricians to determine whether an object is electrically charged. Its internal structure is a two-electrode bulb, the bubble filled with neon gas, commonly known as neon, its one pole to the nib, the other pole in tandem with a high resistance to the other end of the pen. When the voltage between the two poles reaches a certain value, a glow is produced between the two poles, and the glow is directly proportional to the voltage between the two poles. When the charged body to the ground voltage is greater than the glow voltage of the opening of the Neon bubble, and the pencil pen tip contact with it, the other end is grounded through the human body, so pencil will glow. The resistance in the pencil is used to limit the current flowing through the human body to avoid danger.