Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It can be replaced with LED with appropriate series resistor. Transistors may be modern equivalents.
This 10-transistor radio was found in Radio Electronics magazine from December 1964. The...
This oscillator uses one of the four ports of a 74C14 integrated circuit and can generate 100 kHz...
This simple humidity alarm circuit includes a timed warning oscillator whose time is set to R4....