Advantages of varistors compared to other capacitors

1) Better thermal characteristics

Unlike silicon diodes, which have only one P-N junction to withstand surge current, zinc oxide varistor is composed of millions of P-N junctions. This structure has better capacity to absorb and surge withstand capability.

2) Fast response speed

Varistors have similar operating characteristics to other semiconductor devices. Because the conduction of the varistor occurs very fast and the delay is only in the nanosecond range, it can meet any practical needs.

3) Stable voltage under over-temperature conditions

In the case of exceeding the breakdown voltage, once the ambient temperature exceeds the normal operating temperature range, the limiting voltage of the Zener diode will increase as the ambient temperature increases, while the limiting voltage of the varistor exceeds the operating temperature range. The situation remains almost constant. When the leakage current of the varistor increases as the temperature of the element body increases, the limiting voltage of the varistor does not change with the temperature.

4) Capacitance

Compared with Zener diodes, the varistor has a higher capacitance value. Depending on the application area, the capacitance value of the surge suppressor is different. In DC circuits, the capacitance of the varistor can The decoupling effect can play the dual role of suppressing transient overvoltage.

5) Low cost

Compared with diodes, varistor has the advantages of low cost and small size.