This very low power amplifier is designed by Amperex for hearing aids. It is based on TAA370 which is not an integrated circuit that can be found today.
We found this circuit in an old American documentation. SCRs can be modern equivalent types. The...
When the voltage exceeds the value given by the zener, this circuit from a 1990 documentation...
This circuit was found in a 1970s documentation. The components are from that time, and...