It is helpful to compare the formulae for capacitors in series and parallel with the corresponding formulae for resistors (Table 23.3).

Notice that the reciprocal formula applies to capacitors in series but to resistors in parallel. This comes from the definitions of capacitance and resistance. Capacitance indicates how good a capacitor is at storing charge for a given voltage, and resistance indicates how bad a resistor is at letting current through for a given voltage.