Abstract: The microphone of an electronic device is mounted within the housing of the device, and may be a microphone cartridge having a sound opening exposed to a sound chamber within the housing. The device may be a portable radio transmitter and receiver wherein the housing has a wall with a grille screen for providing sound transmission between the inside and the outside of the housing. A cavity is provided inside the housing adjacent the screen for receiving sound to be applied to the microphone. A sound passage connects the cavity to the sound chamber which acts as a reinforcing chamber to apply sound to the microphone. In a radio transmitter and receiver, a loudspeaker may be positioned to project sound through the grille screen, and the cavity between the loudspeaker cone or diaphragm and the screen forms the cavity for collecting the sound.

Abstract: A small plug-in module includes a combined housing and heat sink, and plug-in terminals cooperating with mating terminals on a chassis. The module includes guiding structure to facilitate insertion of the module on the chassis, which may also form terminals for providing a ground connection to the module. The module includes an electronic circuit with components, at least one of which develops substantial heat, such as a transistor. The components are positioned on a substrate which is mounted in heat conducting relation on the base of the housing. The base and/or sides of the housing are constructed to provide sufficient mass to dissipate the heat developed by the components. The housing-heat sink may have recesses into which spring inserts are placed to resiliently engage pins extending from the chassis to guide the module into position and provide a ground connection thereto. Alternatively, terminal pins can be secured to the heat sink to engage sockets on the chassis.

Abstract: A speaker system for a small radio device includes a cover plate having slots therein and a rigid grille screen having channels which extend into the slots. The cover plate and grille screen are generally planar and parallel to each other, and the channels in the screen have portions generally perpendicular to the plate and screen which are spaced from the edges of the slots, with openings therein through which sound is transmitted. A felt disc is positioned over the screen, and the speaker is positioned against the felt disc. An annular bracket engages the speaker rim and is secured to the cover plate to hold the speaker system assembled. The bracket is of semi-circular cross-section with the flat side thereof engaging the speaker, and has integral extensions which are secured to the cover plate to clamp the speaker against the felt disc.