Abstract: A miniature multiturn electrical capacitor is provided that includes low cost, high precision, die cast components and a unique spring biasing means to ensure electrical contact and torque between the rotor and the housing of the capacitor to enhance capacitor performance. The spring biasing means comprises a circular spring which resists compression in the radial direction and engages the inside surface of the flexible tubular rotor to bias the rotor against the internally threaded housing. The torque thus created promotes precise rotor positioning within and electrical contact with the housing.

Abstract: A microphone of the hand held type used in portable or remote radio communications systems in which improved resistance to shock, wet environmental conditions is achieved by using a resilient mounting means for a receiver disposed inside a hollow housing which includes a stop for limiting motion of the receiver in the resilient mounting means and through the use of a loosely mounted water impervious membrane over the active side of the receiver and further disposing an open cell, foamed plastic element over the outside of the plastic membrane.

Abstract: A shock resistant microphone embodying a piezoelectric transducing element that is held in operative disposition with respect to an electrode and a diaphragm by a resilient spring also forming a second electrode.