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 is the average velocity of the balloon, The position-time graph for a ...

The position-time graph for a hot-air balloon that is in flight is shown in the accompanying figure.   a) What is the average velocity of the balloon? b) What is the

Define wave function, It is a mathematical explanation of the disturbance p...

It is a mathematical explanation of the disturbance prepared by a ray. For a string, the wave function is a distance for sound rays. It is a density or pressure fluctuation while f

A high voltage generator, The electrostatic shielding may be found by prote...

The electrostatic shielding may be found by protecting and enclosing the sensitive instruments inside a hollow conductor due to inside hollow conductors, electric fields is zero.

Materials for manufacturing of copper clad laminates, MATERIALS: The bas...

MATERIALS: The basic ingredients of a copper clad laminate are: FILLER RESIN COPPER FOIL FILLER: Fillers are incessant webs of materials like paper

Significant numbers has in a measured quantity, Rules to verify how many si...

Rules to verify how many significant numbers has in a calculated quantity: 1.  All nonzero digits are significant. As like 457 cm has three significant values; 0.25 g has two si

Zeroth law of thermodynamics, Zeroth law of thermodynamics If two bod...

Zeroth law of thermodynamics If two bodies are each in thermal equilibrium along a third body, then all of the three bodies are in thermal equilibrium along with each other.

What is atomic holography, What is atomic holography? Atomic holography...

What is atomic holography? Atomic holography: Atomic holography has evolved out of the growth of the fundamental elements of atom optics. Along with the Fresnel diffraction

How atom was postulated when electrons revolved in orbits, The idea that el...

The idea that electrons revolved in orbits around the nucleus of an atom without radiating energy away from the atom was postulated by: a) Thompson b) Bohr c) Ruther

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