Found in a 1980’s documentation, this circuit must have its signal applied to an amplifier stage. The unijunction transistors can be 2N2646.
This untuned (aperiodic) amplifier circuit was found in the August 1974 Radio Electronics...
The figure shows how to implement an audio power output for an operational stage. With the...
This latching alarm using simple contact relay was found in an English documentation from 1980. The...