The idea behind and uses for the electric pen
One of the equipment that electricians frequently use to check if an object is charged or not is the electric test pen. It has a light bulb-like interior structure with two electrodes. The neon bulb, also known as neon gas, is inside the lightbulb. After a high resistance is connected in series, one pole of it is attached to the tip of the pen and the other pole is connected to the other end. A light will be produced between the two poles of the neon bulb when the voltage between the two poles reaches a particular value; 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 first glow voltage of the neon bulb, and the tip of the test pen meets it, the other end is grounded through the human body, therefore the test pen will emit light. In order to prevent harm, the resistance in the test pencil serves to restrict the current that passes through the body.
When the test pen's tip comes into contact with a charged body with a voltage higher than the neon bulb's initial glow voltage and the other end of the pen is grounded through the body, the test pen will begin to glow. The resistance in the test pencil serves to limit the current that travels through the body to prevent injury.
(2) It can be utilized to differentiate between direct current and alternating current. When using a test pen, alternating current is present if both poles of the neon bulb glow; if only one of the two poles glows, direct current is present.
(3) It is capable of determining the positive and negative direct current poles. The pole on the neon bulb that glows is the negative pole, and the pole that does not shine is the positive pole, thus connect the test pen to the DC circuit for testing.
(4) It can be utilized to determine whether or not the DC is grounded. You can use the test pen to touch either the positive or negative pole of the ground-insulated DC system while standing on the ground. No grounding phenomena exists if the test pen's neon bulb does not light up. A grounding phenomena is present if the neon bulb lights up, and the positive electrode is grounded if the neon bulb lights up as it is on the tip of a pen.That is the negative ground if the light is on the finger end. The method cannot be used to assess whether a DC system is grounded in a system with a ground monitoring relay, it must be noted.
