Contents
What does a varistor do in a circuit?
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. A capacitor may be installed across the signal lines. However, this capacitor cannot suppress voltage surges.
Can we use MOV in DC circuit?
Applications of MOV They can be used for single-phase line to line protection and single-phase line to line & line to ground protection in AC/DC electrical circuits. They can be used for semiconductor switching protection in transistor, MOSFETs or Thyristor and Contact arcing protection in motor-operated devices.
How do I select varistor value?
Therefore, in general, when we select a varistor, the flow capacity should be calculated by pressing the 10 to 100 impacts in the rating curve of the varistor surge lifetime. The actual surge current passed is about 30% of the maximum impact current. (Ie 0.3I).
Where is MOV used?
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.
Varistor is the abbreviation of variable resistor, and the International Electrotechnical Commission (IEC) calls it “voltage dependent resistor” or VDR in its standards. The varistor resistance is related to the voltage applied at both ends.
What kind of resistor is a metal oxide varistor?
A Metal Oxide Varistor or MOV is the blue or orange-colored circular component that you can commonly spot on the AC Input side of any Power Supply Circuit. The Metal Oxide Varistor can be considered as another type of variable resistor that can vary its resistance based on the applied voltage across it.
How does a metal oxide varistor ( MOV ) work?
What is a MOV (Metal Oxide Varistor)? MOV is simply a variable resistor, but unlike potentiometers, MOVs can change its resistance based on the applied voltage. If the voltage across it increases the resistance decreases and vice versa.
How to calculate peak transient current in varistor?
Calculate the peak transient current or the surge current through the varistor. You should select the varistor that has the surge current rating equal or slightly greater than the current rating required by an event that the circuit may produce to make sure it functions properly.