Inductive conversion of position to voltage or current - using non-uniform air gap for non-linear characteristic

摘要

An inductive transducer for the conversion of position into current or voltage uses a three leg magnetic core (1) with a specially shaped central leg (1c) to achieve a non- linear relation between the output and the position of a sensor (2) of electrically conducting non-magnetic material. The central leg has a winding (6) supplied from an oscillator (9). The outer legs (1a, 1b) have secondary windings (3, 4) connected differentially to an amplifier (5) supplying a display (8). The measured variable is linearly represented directly or indirectly by the position of the sensor, which may move along the lower arm (1d) of the core in the air gap between it and the central leg, or radially on a pivot through the lower arm. The couplings between the central winding (6) and the outer windings (3, 4) vary with the sensor position.