Abstract: A transducer is provided for fitting over a rotating shaft to produce a magnetic field about the adjacent area of the shaft when the transducer is energized with an a-c voltage. The transducer includes secondary coils which provide an output signal that varies as a function of stresses developed by the loading of the rotating shaft. The transducer output signals are received by a signal processor which in turn provides output signals for indicating the torque, and/or speed of the shaft. In addition the sense of the torque and speed signals can be shown, and the torque and speed signals can be combined to indicate horsepower.