Can a capacitor increase voltage beyond initial charge?

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SUMMARY

The discussion centers on the behavior of capacitors when charged and then separated. When a capacitor is charged with a 9 Volt battery and the plates are pulled apart, the capacitance decreases, resulting in an increase in voltage according to the formula Q = CV, where Q is charge, C is capacitance, and V is voltage. If the voltage source is disconnected before separating the plates, the voltage can exceed the initial source voltage. This phenomenon is exemplified by the van de Graaff generator, which operates on similar principles.

PREREQUISITES
  • Understanding of capacitor fundamentals
  • Familiarity with the equation Q = CV
  • Knowledge of voltage sources and circuit behavior
  • Basic principles of electrostatics
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Electrical engineers, physics students, and anyone interested in understanding capacitor behavior and voltage dynamics in circuits.

Blackhawk4560
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Question: If you charge a capacitor circuit and then separate the capacitor, does voltage increase beyond the initial source?

It seams counter intuitive that if you plug a 9 Volt battery into two metal plates and pull the plates apart that you'll get massive voltage spikes, but that's what the equations seem to point to...

You'll see a diagram of this attached,
Thanks for your time!
 

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Blackhawk4560 said:
t seams counter intuitive that if you plug a 9 Volt battery into two metal plates and pull the plates apart
Why counter-intuitive ? You yourself already write you need to pull (i.e. do work) the plates apart.

The capacitance decreases, so, in accordance with Q = CV the voltage must increase if the charge remains the same.

By the way, the guy's name is 'van de Graaff'
 
Ohhhhhhhh I hadn't thought of that work being done... makes sense!

Can that lead to the voltage being HIGHER than the initial source? Or does it cap off at the voltage of the battery/van de GraAff?

Thanks again, blown away by that response time by the way!
 
Blackhawk4560 said:
Can that lead to the voltage being HIGHER than the initial source
Yes. Of course, you first have to disconnect the voltage source before starting to pull on the plates.
 

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