How the Electric pen works

As shown in the figure, the inner part of the dashed box represents the structure of the pens. R1 represents the body's resistance, and its lower end is connected to the ground, indicating that people stand on the floor. First connect the pens to the contact point 1, then the equivalent of pens tip to 0 lines, pens both ends of the voltage is zero, neon tube does not glow. The pens is then connected to the contact point 2, which is equivalent to the pens tip to the FireWire, the voltage added to the neon tube over its ignition voltage (about 70 volts) emits a glow.

1. Inert gas characteristic: when a certain voltage is added, the ionization occurs, the free charge is generated in the gas, and the free charge directional movement forms the current. The associated glow when ionized.
2. The human body is a conductor, can also be regarded as a large capacitance, charging discharge ability.
3. The electric field between the FireWire and the human body changes direction with the change of the alternating current direction, and gives the neon bubble a constant change in the direction of the voltage, causing the body capacitance to continuously charge the discharge, the induction current in the neon bubble is maintained, and the glow is aroused.
4. The glow current is faint, without injuring the human body.

5. There is also alternating current in the 0 line, but the electrical potential of the human body is O volts, and the voltage and current cannot be felt.

Test pencil (also known as electric pen) is one of the common tools used by electricians to judge whether an object is charged. Its measuring range is between 60~500v, which has a pen-type and screwdriver-type. by Neon tube (commonly known as neon), resistance, spring, etc., when used, the charged body through the electric pen, the human body and the earth to form a potential difference between the generation of electric field, the neon tube in the electric pen will glow under the action of electric field. The use of electric pen must be properly held, the parent finger and middle finger hold the electric pen insulation, forefinger pressure on the nib metal cap.

How the Electric pen works