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.
In this circuit of a 1968 publication the unijunction may be 2N2646 and the transistor BC548. The...
The purpose of this circuit is to improve a trigger circuit using a zener diode. The circuit was...
This interesting circuit of the American publication Electronics Handbook Volume XIII 1993 shows a...