Benefits Of Metal Oxide Varistor

A varistor is a semiconductor with two terminal. It a device that protects the electronic and electrical devices from the transients that are overvoltage. The resistant is dependent on the voltage that is applied.

This word is formed combining different words resistor and variable. This is also known as a voltage-dependent resistor. The resistance of VDR changes automatically and its correspondence changes with the voltage that crosses it. This is always placed in the shunt and the device is protected. This is generally done to protect the circuit from the surges of voltage.

Construction Or Varistor

When the metal oxides and silicon carbide are pressed in the ceramic materials, varistors

After this, the sintering of the material is done at a very high temperature after which it gets dried. The characteristic of the electrical devices depends on the temperature that is provided and also the atmospheric condition.

To have good electrical contacts, the contact of the material is metallised with copper or silver. Lead is then soldered to the contacts. The varistors are then coded and furnished.

These days the most common voltage clamper is Varistor. These are used for a different range of voltage. It absorbs the destructive energy and it is a non-linear device. It also dissipates it in the form of heat to prevent system damage. At times zinc oxide is used in its manufacturing and therefore it is also called a metal oxide varistor.

A varistor is made with around 90% with zinc oxide and the rest is filler material which forms the junction. A varistor is different from the standard silicon carbide in a way that a MOV exhibits the less leakage current and the operational speed is faster.

 

Get varistor from reliable metal oxide varistor suppliers Delhi.

 

Characteristics And Operation Of Varistor

Before we start with the operation, first we should understand the relationship between the resistance and voltage of varistors. The varistors exhibit the unusual behaviour in case of its resistance. Here as we can see that when the voltage is low then the resistance across it is high. The resistance decreases rapidly with the increase in voltage above the rated voltage.

 

Detailed Operation Of Varistor

When there is a certain low voltage in the device, it offers a very high resistance which happens because of the low current flowing with it. When the voltage increase and then reach clamping voltage, the rated voltage, the current increase. At this particular time, you can notice a change in the operation of the varistor. So after this voltage, the device which was behaving like an insulator then starts to behave like a conductor. So after the voltage resistance is offered, it reduces and allows a very high current pass through it. Therefore it is said that the voltage shows a characteristic of non-linear with the current.

 

Advantage

• This gives excellent protection to overvoltage.

• As it never shows the polar effect, this directionality is then achieved easily.

This shows a widely used in protecting the devices as communication line protection in power supply protection and microprocessor. In cable TV surge and AC protection etc.