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

As cph is a boson, As CPH is a boson, does it has structure? Answer; a ...

As CPH is a boson, does it has structure? Answer; a CPH is tiny energy and it is not a boson. When a CPH takes spin, then it converts to graviton.

Liebig condenser (iron), Liebig condenser (iron) A piece of iron pipe l...

Liebig condenser (iron) A piece of iron pipe line as is used for water or electric conduit can be used to make a metal condenser which is much more robust than a glass one. Inl

Internal resistance of circuit, Internal Resistance of Circuit: As ment...

Internal Resistance of Circuit: As mentioned earlier in the section on batteries, every source of electricity, such as a cell or generator has resistance to current flow called

Rocket observation, At a distance of 4,000 ft from the launch site, a spect...

At a distance of 4,000 ft from the launch site, a spectator is observing a rocket being launched. If the rocket lifts off vertically and is rising at a speed of 600 ft/sec when it

Why hard ferrites are used, Hard ferrites are used for making (A) Tran...

Hard ferrites are used for making (A) Transformer cores.                      (B) Electrical machinery. (C) High frequency equipment.         (D) Light weight permanent m

Volt, Volt; V (after A. Volta, 1745-1827) The derived SI unit of elect...

Volt; V (after A. Volta, 1745-1827) The derived SI unit of electric potential, explained as the difference of potential among two points on a conductor carrying a constant cur

What is the magnitude of the impulse acting on the ball, A ball with an ini...

A ball with an initial momentum of 6.00 kg.m/s bounces off a wall and travels in the opposite direction with a momentum of 4.00 kg.m/s. What is the magnitude of the impulse ac

Explain constant horizontal force, A toy truck is pushed across a table 0.8...

A toy truck is pushed across a table 0.80 m north, and pulled back across the table 0.80 m south. If a constant horizontal force of 15 N was applied in both directions. what

Measure wavelength of light used in newton''s ring experiment, Q. How shall...

Q. How shall you measure wavelength of light used in Newton's ring experiment? Derive the formula used.   Measurement of Wavelength of Monochromatic Light using Newton’s Ri

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