Abstract: A resonant inverter is current mode-controlled with a transistor supplying current through a primary winding of a transformer. The cycle of operation includes conducting, resonating, and clamping portions of the cycle, with the transistor being turned on for the conducting portion. The resonating portion includes a storage capacitor connected to the primary winding and commences when current-responsive means of the transistor or first semiconductor turns on a second semiconductor, which in turn turns off the first semiconductor. During this resonating stage, the current in the primary winding reverses and stores energy in a storage capacitor. A clamping portion of the cycle includes a unidirectional conducting means or diode which conducts for a time for the excess energy stored in the tank circuit to return to the input and be stored in a filter capacitor.

Abstract: A compact surgical operating instrument, including an elongated cylindrical housing supporting a projecting shaft which is mounted for reciprocation by a coaxially arranged cam assembly rotated by a motor drive. The cam assembly includes two continuous, opposed, canted cam surfaces which positively and alternatively drive forwardly and rearwardly a cam follower mounted on the inner end of said shaft, thereby converting rotation of the cam assembly to reciprocal movement of said shaft without the use of return springs.

Abstract: A foot pedal for varying resistance in an electrical circuit having an on-off control is formed having a base member with an actuator foot plate cover pivotally mounted thereto; an array of circular members is positioned in a circular recess between said base member and cover; said array including a pair of electrode discs spaced by a compressible resistance disc; said compressible resistance disc comprising a flexible elastomer with electro-conductive particulate dispersed therein; said array including an actuating plate which has a spherical joint connection with the actuator foot plate cover; an operator's foot pressure compresses the compressible disc to decrease resistance while a spring opens the pedal device when the operator's foot pressure is removed.