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

Explain units and dimensions, Do not confuse units and dimensions. We can u...

Do not confuse units and dimensions. We can use dissimilar units to measure the same physical quantity. So, for example, you can calculate the mass in units of kilograms, poun

Seebeck effect, a) Here temperature difference of junction is used to produ...

a) Here temperature difference of junction is used to produce thermo e.m.f. and vice-versa. b) This effect produced when junctions of a thermocouple are kept at dissimilar tempe

Explain constant current system, Explain Constant current system Const...

Explain Constant current system Constant current system : - In this process, the charging current is kept constant by varying the supply voltage to overcome the enhanced back

What is interference of light, Explain interference of light? Write two ess...

Explain interference of light? Write two essential conditions for sustained interference pattern to be produced on the screen. Illustrate a graph showing the variation of intens

Determine the range of source wavelength values, A weakly guiding fibre wit...

A weakly guiding fibre with a particular graded core index has cut-off V-values for its 2nd, 3rd and 4th modes of 2.5, 3.9 and 5.2, respectively. The core radius is 4 microns, the

Pendulum, #question. all question.

#question. all question.

Explain electric motor, Electric Motor: A device, which converts electr...

Electric Motor: A device, which converts electric energy into mechanical energy is known as Electric Motor. Factors on which the speed of Rotation of Motor Depends: The

Differential equation for a simple harmonic oscillator, Write down the diff...

Write down the differential equation for a simple harmonic oscillator subjected to a damping force proportional to the velocity (v) of the oscillator and the periodic force of angu

Direction of the angular velocity vector, Direction of the Angular Velocity...

Direction of the Angular Velocity Vector In physics, the angular velocity is described as the rate of change of angular displacement and is a vector quantity (more preci

Moving elevator, A moving elevator and a ball or an object being dropped in...

A moving elevator and a ball or an object being dropped inside it with some given speed/acceleration. Ans) You must know the concept of inertial and noninertial frames.non inertia

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