Q V V Charge is forced on to primary plate by voltage Charge is repelled off of secondary plate creating voltage C =
Charging A p.d. across capacitor
R Discharging A p.d. across capacitor
R mA mA Set up this circuit and observe the current flow. Describe it as fully as you can.
What should you have observed? • Current starts high and ends low (0) • Current reduces rapidly to begin with • Current reduces more slowly as time goes on So… Current discharge from a capacitor is Exponential
V R C mA mA Use a voltmeter to investigate the relationship between R or C and the ‘half life’ of the voltage