A Rotary Variable Differential Transformer (RVDT) is an angular position sensor that produces an output voltage proportional to the angular displacement of a laminated rotor stack. This rotor is mounted on a stainless steel shaft that when rotated, moves the rotor to direct greater flux into one secondary of the stator windings thereby increasing the voltage and reduces the flux in the opposing secondary.
The output wave form is a sine function. A full 360° rotation of the shaft will result in either one or two sine wave cycles depending upon the RVDT design. These different designs are referred to as either single cycle or dual cycle RVDTs. The usable linear range for the single cycle is ±80° around electrical zero. The linear range for the two cycle is ±40° around the zero, with the two cycle exhibiting higher accuracy. These angular sensors typically provide MTBFs higher than any other type of angular sensor.