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.
The integrated circuit used is a dual 555 CMOS. The circuit is from an English documentation and...
A 3-input OR gate can be made with an LM3900 amplifier, as shown in the figure. The purpose of the...
We found this conventional power source with a regulating transistor in a 2002 documentation. The...