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 was found in documentation from the 80s. The components are from the time, but the...
We can make an oscillating relay producing a rectangular signal taking advantage of the inductance of...
The circuit shown in the figure is a voltage follower, that is, an amplifier with unit gain. The...