Pulsed torque, force or general measurement with a coil and a magnetic field sensor (tangentially, circumferentially)

A method of measuring torque in a part, for example a shaft, in which at least one coil, wound about an axis of the part about which axis torque is applied, is A.C. energized to create an alternating polarity magnetic field in the part, which field emanates a component dependent on torque. A magnetic field sensor arrangement is responsive to the emanated component to produce a torque-indicating signal. The at least one coil is energized by a series of energizing pulses of current of alternating polarity which pulses have a relatively small duty cycle. The sensor arrangement produces sensor pulses of alternating polarity corresponding to said energizing pulses, and the sensor pulses are measured in a peak-to-peak fashion to produce an output signal representing torque.