This IR light sensor circuit was found in the July 1992 issue of Radio Electronics magazine. It is tuned for 20 kHz modulated light.
Found in the May 1988 issue of Radio Electronics magazine, this circuit is sensitive to small...
Using a 4046 PLL this circuit recognizes a 1.6 to 1.8 kHz tone by driving an output LED. The...
The circuit is from an 80's publication, but the components are current, only special type diodes...