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 circuit was found in a French publication of 1982. The operational can be any with FET as the...
This circuit with SCR was found in an old documentation. The SCR can be the TIC106, and the...
Suggested by Motorola in 1968 documentation, this circuit has an efficiency of 70%. Power...