This receiver for a modulated light intercom was found in a 90s Elektor. The audio amplifier can be replaced by an equivalent. The sensor can be any phototransistor.
This circuit provides a negative supply for circuit biasing. The current is very low. The voltage...
This very low voltage circuit with the LMV321 was obtained from its own datasheet. The circuit can be...
This circuit was found in a Modern Electronics from 1990. It activates an old electromechanical pulse counter,...