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

Explain noise, Noise: An undesirable and unpleasant sound that makes ha...

Noise: An undesirable and unpleasant sound that makes harmful effects on our auditory system is known as noise.

Assuming electrons as classical particals, If electrons are treated as clas...

If electrons are treated as classical particles,which statistics will they follow?

Determine the total circuit resistanc, Two resistors, of resistance 3 and ...

Two resistors, of resistance 3 and 6, are connected in parallel across a battery having a voltage of 12V. Determine (a) The total circuit resistance and (b) The current ?

What does the negative sign signify, In utilizing Kirchoff's Laws to analyz...

In utilizing Kirchoff's Laws to analyze a circuit a student correctly calculates a negative value for one of the currents in the circuit. What does the negative sign signify?

Find the maximum possible efficiency, High temperatures and pressures are g...

High temperatures and pressures are given for the following power plants. ISU co-generation:   400 psi, 750F City of Ames with RDF:   700 psi, 850F Super-critical power pl

Compute the voltage gain with feedback, Q. The voltage increase of an ampli...

Q. The voltage increase of an amplifier without feedback is 100. If negative feedback is functioned with feedback fraction 0.1, compute the voltage gain with feedback. A F

Poission;s theory, what is poission''s equation?Establish poisson''s equati...

what is poission''s equation?Establish poisson''s equation for space distribution of charges.discuss its significance.

Define grand lunar canals, Define Grand Lunar Canals (Moscow Phys-Tech)? ...

Define Grand Lunar Canals (Moscow Phys-Tech)? In one of his book, H. G. Wells illustrate an encounter of amateur earthling astronauts with a lunar civilization living in very d

What are diamagnetic substances, a)      Orbital movement of electrons b...

a)      Orbital movement of electrons b)      On the source of orbital motion of electrons c)       These are repelled in an external magnetic field i.e. have a tendency to g

What is the molar depression constant for benzene, Two elements A and B for...

Two elements A and B form compounds having molecular formulae AB 2 and AB 4 . dissolved in 2O g of benzene, 1 g of AB2 lower the freezing point by 2.3 K, whereas 1 g of AB4 lowers

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