Abstract: A variable capacitor is provided wherein a reinforcing plate is utilized in the rotor assembly in order to increase the range of the capacitor. The capacitor includes the stator plate and first electrode, the stator plate supporting a lead pin and a rotor positioning member, the rotor positioning member being rotatably mounted thereon. The rotor positioning member rotatably supports a uniformly thick rotor assembly in rotatable friction contact with the stator plate and first electrode. The rotor assembly includes a dielectric, a second capacitor electrode and a reinforcing plate, the thickenss of the dielectric determining the minimum value of capacitance of the variable capacitor. The rotor assembly also includes a fixed spring secured to the positioning member, the lead pin and fixed spring being adapted to facilitate use of variable capacitor in small-size electronic instrumentation.