Abstract: A DC/AC converter for supplying two discharge lamps (12, 13). Two input terminals (4, 5) of the converter are interconnected by a series circuit comprising two switching elements (6, 7). A capacitor (8) connects one of the input terminals (4) to a common end (18) of two output circuits (17, 16, 15, 14; 23, 22, 21, 20), one of these output circuits (17, 16, 15,14) also is connected to a junction point (19) between the switching elements (6, 7). A second series circuit comprising two further switching elements (10, 11) is connected to the input terminals. The other output circuit is connected to a junction point (19.sup.a) between the two further switching elements. The converter thus can be readily used both for simultaneously supplying two lamps and for supplying only one lamp.

Abstract: A device for the conversion of acoustic vibrations into electrical waves and vice versa, comprising at least one capacitor electret element which is connected to an electronic circuit which comprises an impedance transformer. The electret element includes at least one foil of a dielectric polymer material with at least one electrode arranged thereon with a part of the foil extending beyond the electret element. The electronic circuit is in the form of an integrated semiconductor device disposed on this part of the foil with the electrode electrically connected to one terminal of the semiconductor device via a conductor arranged on the foil. The foil may comprise a special pattern of conductors and electrodes, to which the integrated semiconductor device is connected. The assembly can be folded to provide a plurality of transducers in the form of a connector pin.