Large (20 cm.) plates mounted to allow any separation distance from 1 to 120 mm. (includes indicator scale). Capacitance from 2.3 to 280 pF. The capacitor is connected to an Electrometer and then charged with a battery. Slowly moving away one of the p lates decreases the capacitance and the voltage measured by the Electrometer will increase. A piece of plexiglass can be used to demonstrate a dielectric.