varisztorokat

A varisztor, also known as a voltage-dependent resistor, is a type of electronic component whose resistance varies with the applied voltage. Typically, varistors are made from semiconductor materials such as zinc oxide. At low voltages, a varisztor exhibits very high resistance, effectively acting as an open circuit. However, as the voltage across it increases, its resistance rapidly decreases. This characteristic makes them particularly useful for surge protection.

When a voltage surge occurs, exceeding a certain threshold, the varisztor's resistance plummets, creating a low-impedance path for the excess current. This diverts the surge current away from sensitive electronic components, thereby protecting them from damage. Once the surge subsides and the voltage returns to normal levels, the varisztor's resistance increases again, and it returns to its high-impedance state. Varistors are commonly found in power supplies, electrical outlets, and other applications where protection against transient voltage spikes is necessary. They are rated by their maximum clamping voltage, which is the voltage that will be present across the varisztor during a surge event, and their energy absorption capability.