19.1.2—C = Q / V

For a fixed capacitor, Q=CV. The slope of a Q–V graph is C.

Use farads, coulombs and volts; identify whether voltage is across the capacitor and account for dielectric or geometry changes before treating C as constant.

A 220 μF capacitor charged to 5.0 V stores 1.1×10⁻³ C.

The capacitor does not store a fixed amount of charge independent of voltage; C is the proportionality constant.