Voltage dependent resistor, Physics

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.

 

Posted Date: 7/9/2012 5:39:36 AM | Location : United States







Related Discussions:- Voltage dependent resistor, Assignment Help, Ask Question on Voltage dependent resistor, Get Answer, Expert's Help, Voltage dependent resistor Discussions

Write discussion on Voltage dependent resistor
Your posts are moderated
Related Questions
A symmetric, multimode slab waveguide has a core width 2ρ, a uniform cladding index n cl and a linear, graded-index profile n(x) in the core that is continuous and symmetric about

Define the graded index multimode fibers intermodal dispersion specifically. In graded index fibers, the index of the core material slowly raises and turns into maximise at the

State two conditions which must be satisfied in order to apply tangent law in magnetism

coaxial vectors



An ostrich can run at speeds of up to 72km/h. Suppose an ostrich runs 1.5km at the speed of 58 km/h and then runs another 1.5km at the speed of 29km/h. What is the ostrich average

Ferromagnetic materials get magnetic properties not only because their atoms owns a magnetic moment but also because the material consists of small regions called as magnetic domai

The number of independent directions in which a system (or gas molecule) can have motion, are called as the number of degrees of freedom of that molecule or object. The number of d

Faraday's second law of electrolysis: The charge Q needed to deposit or liberate a mass m is proportional to the charge z of the mass, the ion and inversely proportional to th