Test method and precautions for varistor

1. Test method of varistor:

(1) First need to know the voltage value of the varistor, you can use a suitable voltage source (the voltage source here can be a common power supply; the protection resistor can avoid excessive current, damage varistor or power supply) in series with a protection The resistor applies a voltage to the varistor and measures the voltage value of the varistor to see if it is at the nominal value. If it is, the component is considered to be good. If there is a large deviation from the nominal value, then the varistor has a problem; (2) the varistor is generally used in parallel in the circuit. When the voltage across the resistor changes and exceeds the rated value, the internal resistance of the resistor sharply decreases. The short-circuit state is presented, and the current fuse connected in series on the circuit is blown to protect. Varistors are used in circuits and are often used for power supply overvoltage protection and regulation. With the varistor three-parameter tester, the varistor voltage, leakage current, and @linear coefficient can be measured. In the case of amateur work, the multimeter is set to 10k when measuring, the test pen is connected to the two ends of the resistor, and the multimeter should display the resistance value indicated on the varistor. If the deviation is large, the varistor is damaged.

2. Precautions for use of varistor:

(1) In the use situation where the inrush current is repeatedly formed, the large instantaneous value of the surge current and the surge energy passing through the varistor cannot exceed the principle of the pulse age;

(2) The varistor cannot be close to the heat and combustible component device. It is recommended to have a gap of not less than 3mm to ensure that it works within the specified operating temperature limit;

(3) The working voltage of the varistor cannot be higher than the value of the large associated operating voltage;

(4) It is recommended to select a protection method for the varistor, so as to avoid the danger that the element is not formed on the varistor and the assembly;

(5) When applying varistor, try to prevent the direct mapping of sunlight, and should not work outdoors or outdoors;

(6) When the peak pulse is repeatedly applied to the varistor with a short interruption, the equilibrium power at this time is made lower than the static power consumption.