This circuit was found in an Elektor from the 90s. It makes use of digital CMOS integrated devices common today. The signal is controlled automatically sequentially.
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...