Synopsis: Van De Graaff Generator

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final year project

Van de graff generator

(Submitted in partial fulfillment of the requirement of the course of B.Tech.)

Babu Banarasi Das National Institute of Technology & Management, Lucknow
Department of Electronics & Communication Engineering

Project Guide: - Submitted by:- Gagandeep BhartiNitin Bharti
Ashatosh Rastogi Sandeep Mohan Sagarwal
Shrutakirti Somvansi
Kundan Pratap Singh
The Van de Graaff generator is an impressive electrostatic generator that is capable of producing enormously large static electric potentials. In fact, giant Van de Graaff generators can produce millions of volts leading to awesome displays of corona and lightning. More modest "class room" sized Van de Graaff generators typically produce 100,000 V to 500,000 V. The Van de Graaff generator is named after Dr. Robert J. Van de Graaff who patented his electrostatic generator in 1935. Interestingly, he developed this generator for studying the acceleration of charged particles to explore the atom. Originally referred to as his "tin can generator", the generator was built using a pure silk ribbon driven by a small motor. The charges on the ribbon were collected on a terminal that actually was a tin can. His early devices were capable of developing 80,000 volts. Of course, this device was limited by the edge effects of the tin can. However, his theory lead to Van de Graaff generators that have produced upwards to 10 million volts. Interestingly, Van de Graaff may not have been the first to develop a belt driven electrostatic generator. In 1893, Von Busch presented a device having two pulleys and a horizontal belt with a charge collector comb and an insulated sphere. Even earlier than this, Rouland invented an electrostatic generator in 1785 using a continuous silk ribbon running between two horizontal pulleys with a collector tube at the center. Regardless of its "true" inventor, Van de Graaff generators have been instrumental in a number of fields, including particle acceleration, electrostatics, ESD, as well as providing an awesome display of the power of electricity.

TWO MAIN PRINCIPALE OF VAN DE GRAFF GENERATOR ARE GIVEN BELOW:- 1) It is designed on the basis of the property that the charge given to a conductor which is hollow inside, is transferred to the outer surface and scatter uniformly over it. 2) It is found on the phenomenon of corona discharge.


There is large spherical conductor name s having a few meter of radius. It is placed on two pillars at a certain height from the ground. One is P1 and other is P2. A made up of insulating material is moving over two pulleys P1and P2.The pulleyP2 is present at the centre of the spherical conductor S and the pulley P1 is present near the ground. A motor is used whose main function is to create a spin in the field. Two sharp headed combB1&B2 are used are used. Spray comb collecting comb are the names of B1&B2. A discharge tube D is used in which the acceleration of ions is done. The point from where the ions originate is present at the head end of the discharge tube. But the other end of tube is earthed.

The whole apparatus is placed in a steel compartment can be filled with discharge. The pressure inside the chamber is maintained very high. Working of Vane De Graff Generator:-
The initial start given to generator is by giving the first comb B1 a positive potential by a strong source near about 104volt.Electric wind having a positive charges will be produced. Production of wind occurs due to the discharging of charge from the sharp edges. Belts move continuously and will reach the sphere an induced negative charge will produced on the other side of the comb B2 after this shifting of the charge it will be transferred to sphere S. Similarly due to...
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