Found in 1968 Mullard documentation, this circuit uses period components. The transistors are matched pairs and the sensor is an Indian photocell of the time.
This thermal control circuit appeared in Radio Electronics magazine in October 1958. The circuit is...
This small medium wave radio was manufactured in the 1960s in Japan. The circuit is powered by 4...
This circuit is from a 1988 publication. It makes use of an LM3914 LED driver circuit, still...