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 volume of bodily fluid, Determine the volume of bodily fluid ...

Determine the volume of bodily fluid A 60.0 kg runner expends 330 W of power while running a marathon (Fig. P11.28). Assuming that9.00% of the energy is delivered to the muscle

Explain n-type substances, N-Type Substances: When a small quantity of ...

N-Type Substances: When a small quantity of Arsenic or Phosphorous (group VA elements) is added to silicon or Germanium, it becomes good conductor of negative charges, such a s

Motion, a rocket is launched at an angle 53 degree to the horizontal with a...

a rocket is launched at an angle 53 degree to the horizontal with a speed of 100 m/s. it moves along its initial line of motion with an acceleration of 30m/s for 3 seconds. at thi

scientific hypothesis or hypothes, 1. A statement of the scientific hypoth...

1. A statement of the scientific hypothesis/hypotheses you have decided to address in your analyses, with a rationale for each. From the rational of the study, the amount of vit

Describe the principle of a moving coil galvanometer, With the help of a ne...

With the help of a neat and labelled diagram, describe the underlying principle and working of a moving coil galvanometer. What is the function of? (i) Uniform radial field

What is friction? what are the factors affecting for it? adv, what is frict...

what is friction? What are the factors affecting for it? Advantages and disadvantages of it

Woodward-hoffmann rules, Woodward-Hoffmann rules: These Rules govern t...

Woodward-Hoffmann rules: These Rules govern the formation of products throughout certain types of organic reactions.

Grounding a positively charged electroscope, Grounding a Positively Charged...

Grounding a Positively Charged Electroscope While the positively charged electroscope is touched and its charge becomes grounded or neutralized this is depicted within the anim

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