This simple metronome, from 1985 documentation uses only transistors and has two settings. For voltages above 6 V, up to 12 V, replace the BC557 with a BD136.
This countdown electromagnetic ring launcher was found in an Electronic Hobbyst Handbook from...
This circuit was found in a 1964 Electronic Design. The circuit delays the firing of a load for a...
This circuit for incandescent lamps was found in a 70s documentation. The circuit uses an SCR...