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Each capacitor has its own selection principle, then about what is the selected standard of varistor, there may be many novice don't know, small make up to do a simple summary, hope I can help you faster familiar with the varistor. Pressure-sensitive resistance is a kind of capacitor that we often use in the circuit, which can effectively protect the circuit from lightning strikes. The selection criteria of the pressure-sensitive resistance are as follows:

For ESD protection of signal transmission lines, consideration must be given to:

1. The operating voltage of the pressure-sensitive resistance is greater than that of the circuit;

2. The electrical capacity of the pressure-sensitive resistance matches the signal transmission rate, that is, the pressure-sensitive resistance does not attenuate the signal when the signal is transmitted;

3. The ESD resistance of pressure-sensitive resistance is in accordance with the requirements of the whole machine.

4. When the signal transmission quality is satisfied, the pressure-sensitive resistance with large electrical capacity is adopted as far as possible, so that the ESD protection effect is good and the energy absorption capacity is improved. (large electric capacity, which may affect the touch button effect, requires testing and verification)

For the power line, the protection of induction overvoltage and operation overvoltage shall be considered:

1. The operating voltage of the voltage-sensitive resistance is greater than that of the circuit.

2. The peak current and energy tolerance of the voltage sensitive resistance must be greater than the induced overvoltage and operating overvoltage amplitude that may occur in the circuit. Under the permission of circuit structure, space position and design cost, the products with large electric capacity or large size are selected as far as possible to improve the energy absorption capacity and increase the reliability of use.

Due to the problem of response time, pressure-sensitive resistance is generally used in the power circuit of anti-surge lightning strike.