Similar to our recent focus on Zener diodes, today we will open another chapter of semiconductor components, specifically varistors. In practice, this component is most often encountered as a protective element, whether it is protection against overvoltage in the supply network or as protection of inductive load switches.
Also, the varistor has many times more capacitance than a diode and thus can absorb many times more energy, but with repeated use the component degrades. Diodes do not have this problem. As a general rule of thumb, a varistor is better for higher voltages and a diode for lower voltages.
A varistor is essentially a voltage dependent resistor. It has nonlinear characteristics and was developed in 1927 based on a copper oxide layer on copper from the work of L.O. Grondahl and P.H. Geiger.
Today's and the most advanced varistors are metal oxide varistors (MOV).
Based on the materials used, different characteristics occur as illustrated in the figure.
We have prepared for you an offer from the manufacturer HITANO, which has been on the market since 1980. Varistors are available in voltages from 8 - 1800Vdc. The maximum energy (10/1000uS) is from 0,05 to 2500 Joules. The varistors operate in temperatures from -40 to +85°C. Tolerances are within 10% or 15%. And they come in three designs, SMD, pin-out and screw-out.
In the attached link you can find all the necessary parameters directly on the manufacturer's website: VARISTORS HITANO