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

Determine the voltage across the capacitor, In the circuit shown in Figure,...

In the circuit shown in Figure, with the switch in position 1, the capacitor is uncharged. If he switch is moved to position 2 at time t =0s, measure (i) The initial curren

Curies law, Curie's law (P. Curie) The susceptibility, khi, of an isot...

Curie's law (P. Curie) The susceptibility, khi, of an isotropic paramagnetic substance is associated to its thermodynamic temperature T through the equation khi = C/T

Decade resistor, DECADE resistors are wire wound resistors. These are wound...

DECADE resistors are wire wound resistors. These are wound on cards moulded on round a switch of low contact resistance. Alloys used for wire are Manganin, minalpha, etc. Bifilar w

Define yttrium aluminium garnet doped with neodymium laser, Define the Yttr...

Define the Yttrium Aluminium Garnet doped with Neodymium laser in short. Nd:YAG laser: a. Nd:YAG, this term stands for Yttrium Aluminium Garnet doped along with Neodymium

Magnetism, what is the principle on which deflection magnetometer work?

what is the principle on which deflection magnetometer work?

Why is the mass of a nucleus less than masses of neutron, Why is the mass o...

Why is the mass of a nucleus always less than the sum of the masses of its constituents, neutrons and protons? If the total number of neutrons and protons in a nuclear reaction

Experiment on thermo electric thermometers, what are some advantages of th...

what are some advantages of the thermo-electric thermometer over the mercury in glass thermometer?

Lamis theorem, a particle of xkg pended by two light inextensible strings o...

a particle of xkg pended by two light inextensible strings of AB and BC of lengths 8cm and 6cm respectively with the mass x attached to B. The end A and C are fixed at the same and

Kinematics in 2-D, If zoe kicked a soccer ball with an initial velocity of ...

If zoe kicked a soccer ball with an initial velocity of 8.25 m/s at an angle of 15.0 degrees, what horizontal distance would it travel?

Determine change in temperature - temperature, 9.8-g lead bullet with a muz...

9.8-g lead bullet with a muzzle velocity of 3.90 x 10 2 m/s is stopped by a wooden block. What is the change in temperature of the bullet if one-fourth of its original kinetic

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