The varistor is a special resistor device which can change its resistance value under the action of external force. The resistance value of the varistor is inversely proportional to the magnitude of the external force, that is to say, when the external force increases, the resistance value will decrease; conversely, when the external force decreases, the resistance value will increase. Therefore, varistors are widely used in a variety of mechanical equipment, play a role in control, protection, measurement and so on.
The resistance value of a varistor is usually expressed in ohms (Ω) or kilo-ohms (KΩ), which represent the basic and larger units of resistance value, respectively. Therefore, if we want to determine the resistance value of a varistor, we need to measure it using an instrument such as a multimeter. In addition, when we buy a varistor, we often see a specific value of how many K of the varistor, and this value represents the nominal resistance value of the varistor.
Voltage-sensitive resistors can be widely used in various fields, such as automotive electronics, consumer electronics, medical equipment, communication equipment and so on. In automotive electronics, varistors are used to control the deployment of air pockets; in consumer electronics, varistors are used for touch recognition of cell phone screens; in medical equipment, varistors are used for blood pressure measurement and pulse measurement, etc.; in communication equipment, varistors are used to protect circuit safety, etc. Therefore, varistors are a very useful electronic component.