The circuit shown indicates voltages from 10 to 14 V used to monitor automotive voltage. One or two LEDs light up depending on the voltage.
Found in an American publication from the 1980s, this circuit is designed to regulate the voltage of...
This 6-transistor Japanese radio from the 1960s used germanium transistors and had an output power...
This simple circuit published in the November 1962 Radio Electronics magazine beeps when the light...