Abstract: A grounding and supporting metal mesh provides connection between a circuit board with a cavity and a housing. The mesh is in the form of a spring made by interconnected torsional members. The mesh is plated with a metal which is compatible with the ground planes of the circuit board and housing.

Abstract: A modular mounting apparatus for substrate means bearing planar circuit means is provided and includes a design of components that assemble into a housing package for microcircuit modules with means for locating, supporting, interconnecting and housing them; in an interference free environment, i.e., provisions for moisture, radio frequency interference and electromagnetic interference sealing are provided. The apparatus provides a modular systematic and economical means of packaging for low frequency printed circuit boards to microwave frequency microcircuits.

Abstract: A light actuated switch apparatus is described in which no movable switch contacts are employed. The switch uses a light source and shutter to activate an array of light sensitive devices to generate a binary code that provides the switching function. One embodiment of the switch apparatus is employed inside a control knob providing a binary code generated by shutter action of a light source on an array of photo-transistors. Another embodiment .[.employes.]. .Iadd.employs .Iaddend.the above control knob including switch apparatus as well as a second knob and printed board to form a dual switch apparatus. As no switch contacts are employed there is considerable reduction in electrical components. Additionally, this also greatly reduces the space required for mounting the switch, is readily serviceable or replaceable as no parts are located within an instrument, and is less expensive as no contacts eliminate any wear and potential problems associated with movable through stationary contacts.