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

Does gravity can bend light?, YES GRAVITY CAN BAND LIGHT e.g. GRAVITY OF...

YES GRAVITY CAN BAND LIGHT e.g. GRAVITY OF BACK HOLE IS VERY STRONG

Describe bernoulli''s theorem, It describes that the total energy (pressure...

It describes that the total energy (pressure energy, potential energy and kinetic energy) of an incompressible and non-viscous fluid in steady flow by a pipe remains constant throu

Discovery of neutron, Write down a short note on the discovery of neutron. ...

Write down a short note on the discovery of neutron. Show the uses of radioisotopes.

Determine the velocity of a wave frequency, The frequency of a wave is 50 H...

The frequency of a wave is 50 Hertz and its wavelength is 25 meters. What is the velocity of this wave? Ans: The velocity of given wave is 1250 meters/second.

Electrostatic potential and capacitance., if a body contain n1 electron and...

if a body contain n1 electron and n2 proton what is the total charge on the body?

Path of the magnetic field produced by the wire, Question: The external...

Question: The external surface of a short vertical segment of plastic pipe is hidden from view by wire wrapped around the pipe. Current flows clockwise as out looked from above

Resistance measurements, Resistance measurements: An example of how to ...

Resistance measurements: An example of how to make AC voltage measurements is shown in the diagram below. Once again, the red and black test leads are connected to the '+' and

Find the resistance of given resistor, Q. The colour codes of a carbon resi...

Q. The colour codes of a carbon resistor are yellow, yellow, orange. Tolerance is 5%. Find the resistance. The initial yellow ring corresponds to 4. The subsequent yellow ring

Trojan points and satellites, Trojan points: It is L4 & L5, the two dy...

Trojan points: It is L4 & L5, the two dynamically stable Lagrange points (under certain conditions). Trojan satellites: This is the satellites that orbit a body at o

Uncertainty principle, Uncertainty principle (W. Heisenberg; 1927): A ...

Uncertainty principle (W. Heisenberg; 1927): A principle, central to quantum mechanics, that states two complementary parameters (such as position & momentum, energy & time, o

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