Abstract: A capacitive transducer for measuring the rotation of a shaft including relatively movable rotor and stator elements. A unique arrangement of capacitive plates is mounted on the stator and rotor for producing a signal indicative of shaft rotation using direct current excitation but without requiring brushes, commutators or slip rings. A preferred embodiment may further include co-planar first, second and third stator plates or alternatively, cylindrically shaped stator and rotor plates. The number of stator plate segments included in each of the first and second stator plates, of the embodiment employing co-planar plates, may be an even multiple less than the number of rotor plate segments. By this arrangement, a circumferential gap may be provided in the first and second plates through which an extension of the third stator plate may be located to reach an output signal terminal located adjacent to but beyond the radial extent of the first and second stator plates.

Abstract: An accelerometer comprising a ferrofluid coated permanent magnet as a proof mass mounted for substantially friction-free movement in a hollow vessel on which vessel are mounted three coils that are used with an electrical circuit to detect and measure movement of the proof mass in response to an outside force and to return the proof mass to a null position.