Found in Unitrode documentation, this oscillator uses some unusual components today such as PU and the 3 M potentiometer. The power can be made with voltages around 15 V.
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...
Found in an Elektor from the 90's, this double door-bell drive circuit switches a relay by...
This simple LED effect is from a 1988 documentation, but it can be easily assembled today, despite...