Capacitance
Energy storage

The energy (measured in joules) stored in a capacitor is equal to the work required to push the charges into the capacitor, i.e. to charge it. Consider a capacitor of capacitance C, holding a charge + q on one plate and − q on the other. Moving a small element of charge d q from one plate to the other against the potential difference V = q / C requires the work d W: d W = q C d q, {\displaystyle \mathrm {d} W={\frac {q}{C}}\,\mathrm {d} q,} where W is the work measured in joules, q is the charge measured in coulombs and C is the capacitance, measured in farads.
combination:two_responses