Test the nine functions and usage of the electric pen application test!
Structural principles:
It is composed of neon tubes (commonly known as neon bulbs), resistors, springs, etc. When in use, the charged body forms a potential difference through the electric pen, the human body and the earth to generate an electric field, and the neon tube in the electric pen will emit light under the action of the electric field.
Instructions:
When using the electric pen, you must hold it correctly. The thumb and middle finger hold the insulation of the electric pen, and the index finger presses the metal cap on the end of the pen.
The tester must be confirmed to be in good condition before use (test at a place with a real power supply) before use.
When in use, it should be gradually approached to the measured object until the neon tube glows before it can be in direct contact with the measured object.
Specific functions:
Function 1: Identify live wire and neutral wire
This is the most commonly used function of the test pen, when measuring AC circuits:
Touch the wire with an electroscope pen, and the glowing neon bulb is the live wire;
The non-luminous part of the neon bulb is the neutral wire (or ground wire).
Function 2: Identify whether there is electricity in the line
This is also the most commonly used function of the electric pen, that is, hold the electric pen in the correct posture and touch the conductor with the pen tip. If the electric pen lights up, it proves that there is voltage in the circuit, and if the light does not light up, it proves that there is no voltage in the circuit.
In actual use, you need to pay attention to whether the circuit is normal or not based on whether the neon bulb of the electric pen emits light or not.
For example, if the live wire and the neutral wire are connected incorrectly under normal conditions, and the neon bulbs of the electric pen glow, this is a fault, and the line must be checked and connected correctly.
Test the nine functions and usage of the electric pen application test! Some electricians really don't know
Function 3: Measure the in-phase or out-of-phase of the phase wire
Circuits that do not distinguish between wire colors will definitely cause headaches during maintenance. The single-phase circuit is fine, but if you encounter a three-phase circuit, it is really a big headache! However, the electric pen has a magical function, which can easily help you measure the in-phase or out-of-phase of the phase wires.
When measuring, hold an electric pen in each hand and stand on an insulating object. Touch the two electric pens to the two wires at the same time. If the brightness of the two electric pens is low, it means that the two lines measured at this time are in the same phase (both are phase lines).
If the brightness of the two electric pens is high, it means that the two lines measured at this time are out of phase (one phase line and one neutral line). With this method, three phase lines and one neutral line in a three-phase circuit can be quickly screened out.
It uses the principle that the voltage difference between the two poles of the neon bulb in the electric pen is proportional to its luminous intensity to judge.
Function 4: Check whether the equipment is leaking
Lightly touch the outer casing of the electrical equipment with the test pen, if the neon tube of the test pen glows, it means that there is leakage.
If it doesn't shine, it doesn't.
Function 5: Identify AC and DC
When testing with a test lead:
If both ends of the neon bulb of the test pen glow, it is alternating current;
If only one end is glowing, it is direct current.
The brightness of the electric pen when measuring alternating current is significantly higher than that of direct current.
Function 6: Identify whether the DC is grounded
In a ground-insulated DC system, you can stand on the ground and touch the positive or negative pole of the DC system with a test pencil:
If the neon bulb of the test pen is not bright, there is no grounding phenomenon.
If the neon bulb lights up, it means that there is a grounding phenomenon, and if it lights up like it is on the tip of the pen, it means that the positive electrode is grounded.
If the light is on the finger end, it is the negative ground.
However, it must be pointed out that in a DC system with a ground monitoring relay, this method cannot be used to determine whether the DC system is grounded.
Function 7: Identify the positive and negative poles of direct current
When measuring direct current, only one end of the neon bulb of the electric pen lights up:
When measuring the positive pole of the DC power supply, the end of the neon tube near the tip of the pen glows;
When measuring the negative pole of the DC power supply, the end of the neon bulb away from the tip of the pen glows.
Function 8. Judging whether the contact is good
If the neon bulb in the test pen flickers during measurement, it may be because the cable head is loose and the contact is poor. It could also be due to unstable voltage.
Test the nine functions and usage of the electric pen application test! Some electricians really don't know
Function 9. Identify whether the bulb is broken or not
Turn off the light bulb switch, and when the light is not on, touch the two terminals of the lamp holder with a test pen. If both ends make the neon bulb of the electric pen glow, but the bulb is not damaged, it means that the neutral wire is broken.
