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.
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...