Abstract: A bone conducting hearing aid comprises a housing adapted to be pressed against a head of a user and a magnetic system held in the hearing aid housing, The magnetic system includes a permanent magnet, a coil, an armature of a soft magnetic material and a spring holding the armature. A conductor button is arranged to move with the armature, the conductor button being shaped to be brought into contact with the mastoid bone of the user's head, and a rubber bearing having a predetermined elastic constant holds a support spring for the conductor button on the hearing aid housing. To increase the difference between the useful signal and the spurious signal received by the hearing aid, the support spring has an elastic constant not exceeding 0.4 N/cm.

Abstract: A single-channel circuit for a hearing aid for persons with an impaired hearing faculty has a pre-amplifier and an output amplifier, a microphone and an earphone, as well as a full-wave rectifier circuit for producing a control voltage for a voltage-dependent attenuator connected to the pre-amplifier. In order to allow a favorable speech audibility characteristic over the entire amplification range, a voltage-controlled filter is provided for a single-dependent change in the frequency response. The control input of the filter is connected to the rectifier circuit. The filter is connected to the rectifier circuit via a time function element.