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

Capacitor construction, Capacitor have thin conducting plates (usually made...

Capacitor have thin conducting plates (usually made of metal) separated by a layer of dielectric, then stacked or rolled to form a compact device. Many types of capacitors are avai

Astronaut catch- momentum and collisions, Astronaut Catch A question su...

Astronaut Catch A question such as this includes momentum principles. In any example in that two objects collide and can be considered isolated from all other net forces and th

Rutherford''s Experiment , My question is that if voltage is increased, the...

My question is that if voltage is increased, the electrons will move faster and the distance between them is changed. Why?

Equivalent resistance, A uniform ring has a radius R with centre C. A nd B ...

A uniform ring has a radius R with centre C. A nd B are 2 pts on the circumference.such that angle theta is 60 0 .find the equivalent resistance between pt A and B? solution) le

Show the condition for dispersion without deviation, Q. Show the condition ...

Q. Show the condition for dispersion without deviation? Q. A thin convex length of focal length 0.1m and a thin concave lens of focal length 0.1m are placed coaxially on contact

Calculate the electric displacement in the dielectric, The plates of a para...

The plates of a parallel plate capacitor are 5 mm apart and 2 m 2 in area. The plates are in vacuum. A potential difference of 10000 Volts is applied across the capacitor. Calcu

Determine the length of the ramp, A skateboard track has a horizontal segme...

A skateboard track has a horizontal segment followed by a ramp that declines at a 45° angle, as shown.   Normal 0 false false false EN-IN X-

Measure the power by the two wattmeter method, Three similar coils, each ha...

Three similar coils, each having a resistance of 8 and an inductive reactance of 8 are connected (a) in star and (b) in delta, across a 415V, 3-phase supply. Measure for

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