Varistors

Electronic component varistor

Variable Resistor

Varistors are electronic resistive components, , a nonlinear semiconductor component with a symmetrical volt-ampere characteristic, the resistance of which changes as a function of the voltage flowing through it. When the voltage value reaches the threshold value of the varistor, regardless of its direction, its resistance is extremely high and practically no current flows through the varistor. The etymology of the word varistor comes from the English words variable resistor, which describes its application. The varistor is used as protection in an electrical circuit where there may be an overvoltage. They are often denoted by the abbreviation VDR (voltage dependent resistor) or resistor dependent on the voltage.

characteristics of varistors

• threshold (operating) voltage
• the working (nominal) current,
• the maximum power dissipated
• the energy that the varistor can absorb

What are varistors used for?

Varistors are connected in parallel to the power supply and are used to protect other elements or devices in the circuit from impulse voltages that can be generated by lightning, switching on, switching off or a fault in the power network. They are a solid state, round, pin electronic element, usually solderable, THT assembly, suitable for alternating and direct voltage AC/DC with a maximum current threshold that it can handle.