This circuit was found in a 1968s European documentation. It is a current regulator using complementary general-purpose transistors.
With a unijunction transistor and a tunnel diode it is possible to obtain rise times of 1 ns with...
The adjustment of the maximum load voltage is made in the trimpot. The circuit is from 1994...
This circuit from a Radio Electronics from February 1976 activates the relay in two different ways...