Voltage dependent resistor, Physics

Assignment Help:

A VDR is a special type of resistor that changes its resistance with rise in voltage. It has a very high resistance at low voltage (below the trigger voltage) and very low resistance at high voltage (above the trigger voltage). It is also called varistor or voltage sensitive resistor. There are two types of varistor.

SILICON CARBIDE VARISTOR:-              

MANUFACTURING: These are made up of silicon carbide. It is milled and mixed with a suitable ceramic binder. Then it pressed and extruded to desired shape of disc, rod or washer. Then it is sintered under controlled temperature to produce hard material. Wire leads are then connected.

METAL-OXIDE VARISTOR (MOV):

MANUFACTURING:

 Zinc oxide and bismuth oxides are mixed with other powdered metal additives, pressed into discs and sintered at 12000C. It has an encapsulated polycrystalline ceramic body; with metal contacts and wire leads.

APPLICATIONS: A varistor acts as a switch. It is usually used for short circuit protection in power strips or lightning bolts "arrestors" on street power poles. It is also used as a "snobbier" in inductive circuits.

 


Related Discussions:- Voltage dependent resistor

What does the negative sign signify, In utilizing Kirchoff's Laws to analyz...

In utilizing Kirchoff's Laws to analyze a circuit a student correctly calculates a negative value for one of the currents in the circuit. What does the negative sign signify?

Wave motion, In an experiment of Quink tube source freequence 100 Hz is use...

In an experiment of Quink tube source freequence 100 Hz is used to find 2nd maxima to 4th manima movalbe part of tube displaced by 1cm then calculate speed of sound in air

Which ship gets hit ?rst, A battleship concurrently ?res two shells at enem...

A battleship concurrently ?res two shells at enemy ships along the trajectories shown. One ship (A) is close by; the other ship (B) is far away. Which ship gets hit ?rst?

Light, what is the wavelength of light

what is the wavelength of light

Phases of matter , Freezing, condensation, and deposition are what kind of ...

Freezing, condensation, and deposition are what kind of processes because heat is removed from matter as they occur

Calculate time of immersion of body into the liquid, A streamlined body giv...

A streamlined body given relative density ρ1 falls into air from a height h1 on surface of a liquid of relative density ρ2 where ρ2 > ρ1. find out the time of immersion of body int

Explain why does heated air expand, Q. Explain why does heated air expand? ...

Q. Explain why does heated air expand? Answer:- Temperature is habitually defined as the average thermal energy of the substance at hand. Therefore the hotter a substance

Explain zener diode and its applications, ZENER DIODE: It is a two termi...

ZENER DIODE: It is a two terminal semiconductor junction device with a very sharp voltage breakdown at reverse bias applied. The device is utilized to give a voltage reference.

Applications of inductors, Inductors are used extensively in analogue circu...

Inductors are used extensively in analogue circuits and signal processing. Inductor in conjunction with capacitors and other components form tuned circuits which can emphasize or f

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd