This kind of Van de Graaff generator is made up of: • A motor • Two rollers • A belt • Two brush assemblies • An output terminal (usually a metal or aluminum sphere) The strong negative charge from the roller now begins to do two things: 1. It repels the electrons near the tips of the lower brush assembly. 2. It begins to strip nearby air molecules of their electrons. Applications: 1. It is used to generate x-rays, which is widely used in medicine field. 2. It is used in atom smasher’s, which is used in research purposes. 3. It found applications in physics, medicine, and astro physics.

1. By:
Ch.anvesh
Ad.No:160711734006

2. Contents
Introduction
Principle of generator
Static electricity
Triboelectric series
Charge developed on material
The Generator
Construction
Charge concentration
Working
Applications
Limitations

3. Introduction

4. Principle of
Generator:
Generally generators works on the
principle of faraday’s law. but, our
Van De Graaff Generator works on
the static electricity concept.
This generator doesn’t have field
winding and conductor.

5. Static electricity:
Static electricity is an imbalance
of electric charges within or on the
surface of a material. if you rub a
glass with a silk cloth, the glass
will develop a static charge that
can attract small bits of papers.

6. The Nucleus:
We know atom consists of nucleus.
Nucleus consists of equal number
of neutron’s and proton’s which
makes atom neutral.
This nucleus is surrounded by
electrons which will rotate in orbit
surrounding nucleus.

7. Triboelectric series:
Some atoms hold on to their
electron’s more tightly than others
do.
How strongly matter holds on to
it’s electron’s determines it’s place
in the ‘Triboelectric series’.

8. Charge developed
on material:
Charge developed depends on:
1. Amount of contact area
2. Humidity-measure of
moisture in the air.

9. The Generator:
The American physicist
Robert.j.Van De Graaff invented
the van de Graaff generator in 1931.
This is the device which can
produce voltages as high as 1
million volts.

10. Construction of
Generator:
Major parts of Generator are:
Motor
Two rollers
A belt
Two brush assemblies
An output terminal(usually a
aluminum sphere).

11. Charge
concentration:
Charge is much concentrated at
roller than at belt, rollers electric
field is much stronger than the
belt’s at location of the lower roller.
The strong negative charge from
the roller now begins to do two
things:
 It repels the electrons near
the tips of the lower brush
assembly.
 It begins to strip nearby air
molecules of their
electrons.

12. Working of
Generator:
As already said it works based on
static electricity principle.
The lower roller induces positive
charge on belt and the belt
transfers the charge to sphere.

13. Applications
1.It is used to generate x-rays,
which is widely used in
medicine field.
2.It is used in atom smasher’s,
which is used in research
purposes.
3.It found applications in
physics, medicine, and astro
physics.

14. Limitations
•Its series connection allows only
one route for the movement of
charges.
•For generating high voltages, size
becomes more and also cost
becomes more.

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