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

Flux, as flux = E.A and flux density is equal to flux/A then why A/A cannot...

as flux = E.A and flux density is equal to flux/A then why A/A cannot e cancelled ?

How do you compute tensile strength, Q. How do you compute tensile strength...

Q. How do you compute tensile strength? Answer:- Tensile strength is not actually calculated it's measured. It is classified as the point at which a sample of material fai

Compute the pitching motion of the spacecraft, A spacecraft design similar ...

A spacecraft design similar to GEOSAT proposes to use passive gravity-gradient stabilization for pitch attitude control (motion about the y-axis).  The satellite consists of a tip

The physics of the brain, in need of projects on '' PHYSICS OF THE BRAIN''....

in need of projects on '' PHYSICS OF THE BRAIN''. Thanks

Pseudo force, define pseudo force and mathematical expression and explanati...

define pseudo force and mathematical expression and explanation

Einstein''s photoelectric equation, Q.   What is Einstein's photoelectric e...

Q.   What is Einstein's photoelectric equation? Explain the laws of photoelectric effect with the help of this equation. Photoelectric Effect : The emission of electron from

Michelson interferometer, Ask question 15. When the movable mirror of a Mic...

Ask question 15. When the movable mirror of a Michelson''s interferometer is moved through a distance of 0.03mm, 100 fringes are displaced, what is the wavelength and color of the

Determine the tension in the cable, The tree needs to fall uphill even thou...

The tree needs to fall uphill even though it is leaning downhill.  The felling notch at O is sufficiently large so that the resisting moment at O is negligible.  The trunk above po

Optical activity and optical rotation, Q.   What is "optical activity and o...

Q.   What is "optical activity and optical rotation"? Write the laws of optical activity of optically active solution. Optical Activity If a plane polarized light is made

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