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

Force, conditions of equilibrium for concurrent force system

conditions of equilibrium for concurrent force system

Explain the magnifying power of an astronomical telescope, The magnifying p...

The magnifying power of an astronomical telescope in the normal adjustment position is 100. The distance among the objective and the eye-piece is 101 cm. Measure the focal lengths

Characteristics of resistance in parallel, Characteristics of Resistance in...

Characteristics of Resistance in parallel: Different amount of current passing by each resistance. i.e. I = I1 + I2 + I3 + I4 ........ The potential difference across every

Circuit theory, what is significance of kirchoff''s law?

what is significance of kirchoff''s law?

#Inductance balanced delta connected load, how to you calculate the inducat...

how to you calculate the inducatnce on a balanced delta circuit?

Determine the current is distributed uniformly over the rod, A copper rod w...

A copper rod which is 1 centimetre in diameter carries a current of 5 amps.  The current is distributed uniformly over the rod.  The magnetic field half way among the axis o

Optics, determination of suger concentration in water by refractive index

determination of suger concentration in water by refractive index

Determine the current flowing by each resistor, For the series-parallel arr...

For the series-parallel arrangement shown in Figure, find (a) The supply current, (b) The current flowing by each resistor and (c) the p.d. across each resistor

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