Sun March 02, 2008 By:


Expert Reply
Wed May 07, 2008

A 'dielectric' is a nonconducting substance, i.e. an insulator

Commercially manufactured capacitors typically use a solid dielectric material with high permittivity as the intervening medium between the stored positive and negative charges. This material is often referred to in technical contexts as the "capacitor dielectric"



van de graff generator:

A Van de Graaff generator is an electrostatic machine which uses a moving belt to accumulate very high electrostatically stable voltages on a hollow metal globe

Van de Graaff generator. The large sphere acts as a capacitor to store the charge transferred up its supporting column. The small sphere (connected to the ground potential) will draw an arc from the larger when the air gap breakdown voltage is exceeded

The potential differences achieved in modern Van de Graaff generators can reach 5 megavolts. Applications for these high voltage generators include driving X-ray tubes, accelerating electrons to sterilize food and process materials, and accelerating protons for nuclear physics experiments. The Van de Graaff generator can be thought of as a constant-current source connected in parallel with a capacitor and a very large electrical resistance.

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