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 is from a 1967 publication. It is possible to power a fluorescent lamp from a 12 V...
This circuit was found in old American documentation. Transistor is general purpose and coil rated...
With a strong positive feedback (via a 10 M resistor) we can get the trigger setting for the...