This circuit is from a 90s documentation. It has a hysteresis and uses a light sensing bridge. The circuit generates a 1000 Hz modulated 10 Hz signal. The signal must be applied to an amplifier.
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...