The working principle of electrician's electric test pen
The electric test pen is one of the tools often used by the majority of electricians to determine whether the object is charged or not.
Its internal structure is a light bulb with two electrodes, which is filled with neon gas, commonly known as neon bulb.
When the voltage between the two poles of the neon bubble reaches a certain value, a glow is generated between the two poles, and the intensity of the glow is proportional to the voltage between the two poles.
When the voltage of the charged body to the ground is greater than the glow voltage of the neon bulb, and the tip of the test pen touches it, the other end is grounded through the human body, so the test pen will emit light.
The function of the resistance in the test pen is to limit the current flowing through the human body to avoid danger.
