GB1348735A - Electro-acoustical transducers - Google Patents

Abstract

1348735 Transducer; diaphragms SIEMENS AG 5 April 1972 [23 April 1971] 15566/72 Heading H4J A transducer consists of a housing containing a diaphragm 10 which is gripped in its peripheral region by a resilient body 8 that rests on the end face of a hollow cylinder 4 containing a disc which is disposed non-centrally of the (height) of the cylinder so as to define unequal size resonant volumes with the rear face of the diaphragm in dependence on which way round the cylinder is located in the housing. The latter criterion permits the transducer to be used interchangeably as a microphone or a telephone receiver. The disc may be hollow with apertures connecting its inner space to one only of the volumes (Fig. 2, not shown) or to both volumes (Fig. 3, not shown). The end faces 6, 7 of the cylinder may have different internal diameters, this feature forming the subject of Specification 1,348,734. A piezo-electric layer 9 may be formed on the diaphragm. The casing consists of two parts 1, 2, with apertures 3 being provided in the front cover part 2. An amplifier may be incorporated in the hollow disc, connections therefrom being made to a conductive layer on the diaphragm.