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 exaggeration produced by the two lens system, Q. (a) Determin...

Q. (a) Determine the'effective  focal length' of the grouping of the two lenses in Exercise 9.10 if they are placed 8.0 cm a part with their principal axes  coincident. Performed t

Determine single capacitance for 2-farad & 4-farad capacitor, A two farad a...

A two farad and a four farad capacitor are connected in series. What single capacitance is "equivalent" to this combination? A 2-farad and a 4-farad capacitor are connected in

A sodium cation has different number of electrons from, A sodium cation has...

A sodium cation has different number of electrons from: (1) O 2-                  (2) F -       (3) Li +                    (4) Al +3 Ans: Li +

Special resistor materials: nichrome, Nichrome: Nichrome is an alloy of Ma...

Nichrome: Nichrome is an alloy of Manganese 1.5%, nickel 75% to 78%, chromium 20% to 23% and a little percentage of iron. Properties: 1.      Its elec trical resistivity

Describe what is one beat , If the intensity of sound is maximum at time t ...

If the intensity of sound is maximum at time t = 0, one beat is known as formed when intensity changes into maximum again after becoming minimum once in among.

New potential difference, A parallel plate capacitor has plates of area 200...

A parallel plate capacitor has plates of area 200 cm 2 and separation among the plates 1.00 mm. What potential difference will be manufactured if the charge of 1 nC is given to th

What is the angle of reflection, Question As-per to the law of reflect...

Question As-per to the law of reflection the angle of reflection is equal to the angle of incidence. An angle is at all times an angular separation between two planes a direct

1 farad, 1 Farad: One farad is described as the capacity of that capaci...

1 Farad: One farad is described as the capacity of that capacitor which keeps a charge of 1 coulumb, if the potential difference among the plates is one volt. It's equation

Two simple harmonic motions have the same periodic time, When the two simpl...

When the two simple harmonic motions have the same periodic time but different amplitude and a phase dissimilarity = ∏/2: The resultant curve may be attained graphically as abov

Manufacturing of transformers, Before manufacturing of transformers we must...

Before manufacturing of transformers we must know the important parts of transformer which need to be manufactured. Following are the main parts of transformers. (a)          Fo

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