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.
The use of field effect transistors in this circuit improves its performance. This configuration is from a...
This is a simple source indicated for powering low voltage projects on the bench. The circuit is...
This circuit was found in a 1969s American documentation. With modern components, it can be used...