Abstract: The present invention relates to an miniature actuator especially suitable for hearing aid applications. The actuator according to the present invention operates according to the change in reluctance principle. In particular, the actuator according to the present invention operates in a balanced configuration comprising two planar coils, two magnets, a membrane and a spacer chip providing the necessary back chamber volume.

Abstract: A method of manufacturing a transducer of the type having a diaphragm (11) with a predetermined tension. After the transducer has been manufactured with its basic structure the diaphragm is adjusted to have a predetermined tension, which is preferably low in order to obtain a high sensitivity. Two embodiments are disclosed. One embodiment includes heating the transducer to a temperature above the glass transition temperature of the material (12, 14) retaining the diaphragm. Another embodiment includes measuring the actual tension of the diaphragm, which can be used to calculate an adjustment of the thickness of the diaphragm resulting in the desired tension.