Electrostatics
The Van de Graaff Generator
What is it?
A Van de Graaff generator is a device that can grab and transfer large charges. Van de Graaf generators have been used in atom smashers. A Van de Graaff generator can accelerate particles to very high speeds.
Where did this come from?
The American physicist Robert Jemison Van de Graaff invented the Van de Graaff generator in 1931. The device that bears his name has the ability to produce extremely high voltages as high as 20 million volts. Van de Graaff invented the generator to supply the high energy needed for early particle accelerators. These accelerators were known as atom smashers because they accelerated sub-atomic particles to very high speeds and then "smashed" them into the target atoms. The resulting collisions created other subatomic particles
How does it work?
There are two types of Van de Graaff generators: one that uses a high-voltage power supply for charging and one that uses belts and rollers for charging. The one that uses belts and rollers will be the one I will talk about. When the motor is turned on, the lower roller (charger) begins turning the belt. Since the belt is made of rubber and the lower roller is covered in silicon tape, the lower roller begins to build a negative charge and the belt builds a positive charge. Since silicon is more negative than rubber the lower roller is capturing electrons from the belt as it passes over the roller.
How Does a Van de Graaff Generator Work?
Internal construction
The internal construction that shows how the charges move and where.
Two Van de Graaf Generators
Two Van de Graaf Generators standing side by side
Operation
"A spark was generated between the two metal balls when it was operating."
Citations
Zavisa, John. "How Van De Graaff Generators Work." HowStuffWorks. HowStuffWorks, 4 Apr. 2003. Web. 20 Feb. 2013.
Hua, Tang Wee. "Van De Graaff Generator." Van De Graaff Generator. University of Kentucky, 15 Feb. 2005. Web. 20 Feb. 2013.