This circuit is from an English documentation from 1969. The circuit can be designed based on modern equivalent transistors. Diodes are general purpose types.
In this circuit of a 1968 publication the unijunction may be 2N2646 and the transistor BC548. The...
This circuit was found in a 1969 CQ magazine. It is intended for coupling telephones to radio...
This circuit, which can be used as a shield, was found in Radio Electronics from the 90s. The...