This circuit was found in a 80's Popular Electronics. The sensor can be any phototransistor. The circuit is indicated for an audio link modulated in pulses.
Found in a 1980s documentation, this circuit uses a photo-Darlington. There must be an optical...
We have here an ultra-simple amplifier stage of just one transistor, which can have some uses on...
This conventional window detector circuit was found in a 1995 documentation. The trigger points, that...