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

Kinematics, an aeroplane is moving horizontally with a velocity of u . it d...

an aeroplane is moving horizontally with a velocity of u . it drops a packet from a height h. the time taken the packet in reaching the ground is?

Digital electronics: binary system, (i) A number system which has only two ...

(i) A number system which has only two characters i.e. 0 (Low value) and 1 (High value) is known as binary system (ii) The electrical circuit which operates only in these two di

Explain working of common-emitter amplifier, State whether the following s...

State whether the following statements are true or false: (a) The purpose of a transistor amplifier is to enhance  the frequency of the input signal. (b) The gain of an ampl

MOTION, MOTION EXAM WITH ANSWERS

MOTION EXAM WITH ANSWERS

Electromagnetic induction, key headings in project file of electromagnetic ...

key headings in project file of electromagnetic induction

Superconductivity, Superconductivity The phenomena from which, at suff...

Superconductivity The phenomena from which, at sufficiently low temperatures, a conductor can conduct charge along with zero resistance. The current theory for describing supe

Prepare a marketing plan, Using the information that you already know about...

Using the information that you already know about the business and its products, and through consideration of the PEST and SWOT factors, you are required to prepare a brief

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