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Equipment

Wimshurst Machine
AKA: Electrostatic Generator

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Fig 1: Typical Wimshurst machine with Leyden jars
Fig 1

Summary

A machine which uses electrostatic induction to create very high voltages.

Operation

The Wimshurst machine is a device that was used prior to the now familiar Van De Graff generator to produce very high voltages in the lab. Whereas Van De Graff generators use belt friction to achieve these high voltages, the Wimshurst device uses two contra-rotating plates mounted on a vertical plane. These plates become electrostatically charged and transfer their charge to a set of combs which may be connected to a pair of Leyden jars which act as crude capacitors. These can then be discharged through a pair of metal spheres to produce a significant spark. Wimshurst machines are still available through lab suppliers today although they have generally been superseded by the Van De Graff machines in school physics lessons mainly due to cost and the array of practicals associated with the V.D.G.

Be aware that discharging near electrostatic sensitive devices may result in damage; USB memory sticks, mobile phones, computers, some watches, MP3 players, televisions, VCRs etc may contain or are connected to sensitive memory chips.

Safety

 ElectricityThe contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.

Notes

The Wimshurst machine as we now know it was invented in 1878 by James Wimshurst.