Found in a 90s Popular Electronics, this sensor operates by infrared reflection. The components are modern, and the phototransistor can be of almost any type.
This 0.5 Hz filter was found in the December 1990 issue of Radio Electronics magazine. The power...
This circuit was obtained in the SGS manual of linear integrated circuits of 1982. The maximum...
This circuit allows linear brightness control of an LED from an input voltage. The power supply must...