How do I choose a varistor?
Choose a varistor with an energy absorption rating that equals or slightly exceeds the energy values associated with the event the circuit may experience. If, however, the transient voltage is due to an external event, the magnitude of the source energy is unknown.
What is a metal oxide varistor used for?
Varistors are used to protect a circuit from high voltage surges. When a high voltage surge is applied to a circuit, the outcome is usually catastrophic to the circuit.
What is MOV and how it works?
An MOV is a voltage dependent device which has an electrical behavior similar to back to back zener diodes. changes from a near open circuit to a very low value, thus clamping the transient voltage to a safe level. pulse is absorbed by the Varistor, thereby protecting vulnerable circuit components.
Why we use MOV in circuit?
A Metal Oxide Varistor (MOV) is a protection component used in power supply circuits that is powered directly from AC mains. It is used to protect the circuit from high voltage spikes by varying its resistance.
What is the purpose of a MOV?
What kind of varistor is used for 24VDC?
The AUMOV Series Varistor is designed for circuit protection in low voltage (12VDC, 24VDC and 42VDC) automotive systems. This series is available in five disc sizes with radial leads with a choice of epoxy or phenolic coatings.
When to measure the voltage across a varistor?
The voltage across a varistor when a current of 1 mA is passed through the component. The measurement shall be made in as short a time as possible to avoid heat perturbation. The varistor voltage is essentially a point on the V/I characteristic permitting easy comparison between models and types. MAXIMUM CLAMPING VOLTAGE
How to design a DC application varistor uide?
DC Application Varistor Design uide www.littelfuse.com3 About the AUMOV Series Varistor The AUMOV Series Varistor is designed for circuit protection in low voltage (12VDC, 24VDC and 42VDC) automotive systems. This series is available in five disc sizes with radial leads with a choice of epoxy or phenolic coatings.
How is the dissipation of a varistor calculated?
When a sinusoidal alternating voltage is applied to a varistor, the dissipation cannot be calculated from the same formula as in a DC application. The calculation requires an integration of the V x I product. The instantaneous dissipated power is given by: In the above equation, the value V = V peak x sin t.