When
a voltage is applied to a circuit containing capacitance, current flows to
accumulate charge in the capacitance:
**Q = **ò**idt = CV**
Alternatively, by differentiation with respect to time:
**dq/dt = i = C dv/dt**
Note that the rate of change of voltage has a polarity which
opposes the flow of current.
The capacitance **C** of a circuit is equal to the charge
divided by the voltage:
**C = Q / V = **ò**idt
/ V**
Alternatively, the capacitance **C** of a circuit is equal to
the charging current divided by the rate of change of voltage:
**C = i / dv/dt = dq/dt / dv/dt = dq/dv** |