This well-designed bistable circuit was found in a 1970s documentation. Transistors can be current types and germanium diodes. The voltage depends on the logic used and can be made with 5 V.
.
This polarity test or indicator indicates the polarity of a power line by LEDs. The circuit is...
This is the circuit of a digital clock published in the January 1975 issue of Radio Electronics magazine....
Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The...