Hearing aid amplifier circuit

摘要

A hearing air amplifier circuit is proposed which, apart from a microphone, exhibits a telephone coil which can be connected by means of a change-over switch. The change-over switch (18) is located between two successive amplifier stages (15, 23). Whilst the alternating voltage of the microphone (10) is amplified in the first and the following amplifier stages, the alternating voltage of the telephone coil (20) is only amplified in the second and in the possibly following amplifier stages of the hearing aid amplifier circuit. <IMAGE>