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

Describe the numerical aperture in the optical fibre, Describe the numerica...

Describe the numerical aperture in the optical fibre. Numerical Aperture: The numerical aperture is described as the sine of the acceptance angle. Therefore, Numerical

Elementary Mechanics, A bird flies in the east direction with a speed of 5 ...

A bird flies in the east direction with a speed of 5 ms-1. The wind is blowing towards north at a speed of 3 ms-1. Determine the relative velocity of the bird with respect to the w

Explain axis of rotation - force, A child starts to build a house of cards ...

A child starts to build a house of cards by laying an 8.5-cm-long playing card with a mass of 0.75 g across two other playing cards: support card A and support card B. If suppor

Michelson''s interferometer construction and working in detai, Construction...

Construction and working of michelson''s interferometer in detail

Explain joule''s law, Explain Joule's Law: "Work done is directly propo...

Explain Joule's Law: "Work done is directly proportional to the heat produced.

Displacement of a small distance, how to use instruments like Vernier calip...

how to use instruments like Vernier calipers and micro screw gauge to measure round objects

Resistors and resistors characteristics, A resistor is a two-terminal elect...

A resistor is a two-terminal electrical or electronic component that resists an electric current by producing a voltage drop between its terminals in the accordance with ohm’s law.

Gray, Gray; Gy (after L.H. Gray, 1905-1965): The derived SI unit of ab...

Gray; Gy (after L.H. Gray, 1905-1965): The derived SI unit of absorbed dose, described as the absorbed dose wherein the energy per unit mass imparted to the matter through ion

Flow in the coil as a result of the motion of the magnet, A bar magnet is o...

A bar magnet is overhanging north end up well above a vertical coil of wire. The bar magnet is released and as it falls down toward the coil it falls along a path that will take it

Determine the power supplied to the load, A single-phase transformer has a ...

A single-phase transformer has a voltage ratio of 6:1 and the h.v.winding is supplied at 540V. The secondary winding gives a full load current of 30A at a power factor of 0.8 l

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