An Introduction to Ultrasonic MotorsThe ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide its motive force, resulting in a motor with unusually good low speed, high torque, and power to weight characteristics. This introduction to the general theory of the ultrasonic motor was written by the motor's inventor and an expert in conventional electric motors. It details many of the motor's applications, including in camera