This circuit was found in the 1990 Motorola Dataar Linear. We can mount it with more modern equivalent transistors. Output transistors shall be provided with heat radiators.
We found this timer for times of a few minutes in a 1974 Ferranti transistor manual. The relay is 37...
The SCR sector of this circuit can be powered by high voltage AC and instead of the LEDs we can...
This circuit was found in a 73 amateur radio magazine from the 90s. An LED extends the scale from 0...