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Van de Graaff generator
Intermediate
Builds up high voltages by charge transfer on a belt.
A moving belt carries charge to a hollow metal dome, where it spreads to the outside surface, raising the potential to millions of volts. Used for accelerating particles and demonstrations.
Makes hair stand up.
Charge builds until air breaks down.
In more detail
A Van de Graaff generator builds up very high voltages by carrying charge on a moving belt to the inside of a hollow metal sphere. Charge collects on the outer surface.
Real-world uses
- Van de Graaff generators demonstrate electrostatics in classrooms and museums.
- Particle physics used them to accelerate particles historically.
- Physics teachers use a Van de Graaff generator to show high-voltage effects, such as hair standing on end.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Why is the charge on the outside?
Because charge on a conductor moves to the surface to minimise energy.
Is it dangerous?
It can give a painful shock but is usually low-current and not lethal.
How does the generator build up charge?
A moving belt carries charge to a hollow metal dome, where it accumulates on the outside surface.
Related topics in Electrostatics
Dielectric breakdown · Spherical capacitor · Cylindrical capacitor · Lightning and discharge · Photocopiers and electrostatic precipitators · Millikan oil drop experiment