This circuit turns off a load after an interval of 8 to 80 seconds adjusted on the potentiometer. The circuit is from a Radio Electronics June 1970. The time depends on C1 and can be changed.
This sequential light effect was obtained in a 1992 documentation, but it can be easily assembled...
This simple Hartley circuit can generate two tones depending on the adjustment of the trimpots. The...
This 2.5 A power supply was found in a 90's QST magazine. The power transistor must be mounted on a...