The internal composition of the electric test pen and the dangers of damage to the electric test pen
If the resistance of the test pen is broken, what will happen when measuring the live wire? The probability of electric shock is relatively high, because whether the internal resistance is reduced or the circuit is broken, it will cause misjudgment and lead to live operation.
The internal components of the test pen
The traditional electric test pen has a very simple structure, consisting of a high-resistance resistor, a neon bulb, a spring and a pen cap. The neon bulb does not emit light under low voltage conditions and generally lights up above 100v. It is difficult to damage unless it is dropped.
The resistance of high-resistance resistors varies. In theory, a resistance greater than 500k ohms can meet the needs. However, we hope that the resistance is as large as possible. Of course, it cannot be infinite. Then it will be open circuit and will not emit light when measuring charged objects. It is easy to Let us make misjudgments, so electric pens need frequent inspection and maintenance.
So what happens if the resistance in the pen is lower than the set value? Obviously, the human body is prone to electric shock when an electric pen comes into contact with a live object. I believe everyone, especially electricians, has learned this lesson.
The dangers of damage to the test pen
Misjudgment caused by infinite resistance may cause us to think that the electrical appliance has no power, which may cause the risk of electric shock during maintenance operations and cause great harm to the human body.
A test pen with a resistance lower than 500k ohms will cause people to feel numb when measuring a charged object. If the resistance is lower, it is equivalent to touching a live wire with your hand, and the consequences will be serious.
Summarize
When purchasing an electric test pen, you can bring a multimeter to check the resistance of the internal resistor. Generally, it is above the MΩ level, indicating that it is of excellent quality and can be used for a long time.
