Northwestern Physics Demos                                 Go back to Electricity
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DCS# 5C30.20NU# E-40Location:    11 A 2
title: Capacitor Stored Energy
aka:     Short a capacitor

  A fairly large electrolytic capacitor is charged by a bank of 9 V batteries, then discharged by shorting with a screwdriver.
  Various voltages can be applied by changing the number of batteries, or by adding a volt meter and using time to determine the voltage on the capacitor.
1.   Sparks will fly!  Use safety glasses!  
2.   The capacitor is polarized, be sure to hook up the battery properly.  (+ to +)
3.  Be doubly sure the capacitor is completely discharged before handling.

    How does the energy stored in a capacitor depend on the voltage achieved during charging?   If the voltage is doubled, how much does the energy stored increase?

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