# CAPACITOR

**Learning Outcomes**

22.1 capacitance and capacitor

a. Show understanding of the uses of capacitors in simple electrical circuits

b. Define capacitance as the ratio of the change in an electric charge in a system to the corresponding change in its electric potential and associate it to the ability of a system to store charge

c. Use C=Q/V

d. Relate capacitance to the gradient of potential-charge graph

22.2 Parallel plate capacitor

a. Derive �, using Gauss law and � , for parallel plate capacitor

b. Explain the effect on the capacitance of parallel plate capacitor of changing the surface area and separation of the plates

c. Explain the effect of a dielectric in a parallel plate capacitor in

22.3 Combination of capacitors

a. Derive formula for combined capacitance for capacitors in series combinations

b. Solve problems related to capacitors in series combinations

c. Derive formula for combined capacitance for capacitors in parallel combinations

d. Solve problems related to capacitors in parallel combinations

22.4 Energy stored in a charged capacitor a. Deduce, from the area under the potential-charge graph, the equations ��Ñ‰and hence ��Ñ‰ for the average electrical energy of charged capacitor 22.5 Effect of dielectric

b. Show understanding of a dielectric as a material that polarizes when subjected to electric field

c. Explain the effect of inserting dielectric between the plates of a parallel plate capacitor on its capacitance