Introduction Capacitance Incomplete capacitor circuits Charge flow Storing charge Stored charge: effect of voltage Capacitance formula Stored charge: other factors Designing capacitors (1) Designing capacitors (2) Energy stored in a capacitor How much energy is stored? Stored energy: graphical view Charging through a resistor Analysing the charging data Discharging a capacitor Analysing capacitor discharge
 
By Jeff Preston, NewtonleWillows Community High School
Paul Berry, MATTER Project
A capacitor is an electronic component which is used in a wide variety of
circuit applications due to its ability to store charge.
Learning outcomes
After completing this section, you should be able to:
 provide a definition of capacitance and name its units; 
 explain how a capacitor can be produced to give a particular value of capacitance.
To do this, you will need to:
 recall and use an equation which relates capacitance to charge (Q) and voltage (V); 
 recall and use an equation which relates capacitance to the plate separation (d), area (A)
and dielectric permittivity (e); 
 describe briefly what is meant by the term permittivity and state its units; 
 explain that permittivity is a material property; 
 explain the term relative permittivity, e_{r}, and state its units; 
 explain why e = e_{0}e_{r}; 

 explain why a capacitor has a maximum working voltage; 
 determine experimentally the energy stored in a capacitor; 
 explain the terms "halflife" and "time constant" as applied to
capacitor circuits; and 
 determine experimentally the "halflife" and "time constant" of a
capacitor/resistor circuit. 
Assumed prior knowledge
It is assumed that you have knowledge of the following concepts:
 basic electrical terms such as voltage, current and charge. 
