Capacitors A2 Powerpoint

Physics, Electricity and Circuits, Age 16-18

Powerpoint on Capacitors for teaching Edexcel A2 Unit 4, including formulas for charge, energy stored in capacitors and current / voltage at a given time


1Capacitance !!2A capacitor is a device that stores energy by separating charge. Placing charge on the capacitor results in potential difference. The capacitance (C) of a system is defined as the charge stored, Q, per unit potential difference, V.3Pictures of Capacitors4Symbol for CapacitorDielectric insulating materialConducting PlatesAs plates need to be quite large to hold charge they are rolled like a swiss roll. 56FormulaC = Q / V 1F = 1CV-1Typically Capacitance ranges from μF (10-6) to pF (10-12)7ChargeTo measure the capacitance of a capacitor we must know the charge on it’s plates.If the current is constant we can use:- Q = I x t8Circuit Diagram9Energy stored in CapacitorEnergy is transferred to the capacitor by the power supply or battery. It behaves similarly to a rechargeable battery The p.d. and the size of the capacitor affect the energy stored:-Energy Stored (W) = ½ x Capacitance (C) x p.d. (V) 2W = ½ C V 2