Electrostatic Potential and Capacitance

The underlying principle of Van de Graff generator is that a charge given to a hollow conductor is transferred to the outer surface and is distributed uniformly over it. 

 

Construction: It consists of a large hollow metallic sphere S mounted on two insulating columns A and B and an endless belt of rubber or silk is made to run on two pulleys P₁ and P₂ by the means of an electric motor. C₁ and C₂ are two sharp metallic spikes in the form of combs. The lower comb C₁ is connected to the positive terminal of a very high voltage source and the upper comb C2 is connected to the inner surface of metallic sphere S. 

 

Uses:

1. Used to accelerate charged particles such as electrons, protons, ions etc, used for nuclear disintegration.

Limitations:

1. The generator allows only one route for the movement of charge as it is a series combination.
2. It can accelerate only charged particles and not the uncharged particles.