Working of Varistor
The working principle of varistor is based on its nonlinear voltage-current characteristic. When the voltage across a varistor exceeds its specified threshold and its resistance decreases significantly allowing it to conduct current and shunt the excess voltage away from protected circuit. This effect is achieved due to semiconductor properties of varistor material.
- Normal Operation: The Under normal operating conditions. where voltage remains below the varistor’s threshold and it behaves as a high-resistance component effectively isolating the circuit from the voltage spikes.
- Surge Conditions: When a voltage surge or transient occurs exceeding the varistor’s clamping voltage the varistor undergoes a rapid transition from a high-resistance state to low-resistance state.
- Conduction: The varistor effectively shorts the excess voltage across its terminals is allowing a significant surge current to flow through it.
What are Varistors ?
A Varistor is an electronic component designed to protect electrical circuits from excessive voltage surges or transients. It is a nonlinear resistor whose electrical resistance varies significantly with changes in voltage. Varistors are commonly used to safeguard sensitive electronic devices and equipment by diverting excess voltage away from them.
Varistors are frequently employed in parallel with the devices or circuits they are designed to safeguard. When there is a voltage spike, the varistor effectively “clamps” the voltage at a safe level, keeping it from reaching the protected components. The varistor recovers to its high-resistance state after the surge has passed.
Table of Content
- Definition
- Varistor Symbol
- Packages
- Construction of Varistor
- Types of Varistor
- Operation and Characteristics Graph
- Properties of Varistors
- Characteristics of Varistors