The capacitors on this circuit determine the frequency that this circuit can detect. We can adapt it to work as an interesting shield detector for logic signals.
The phototransistor can be of any type and the adjustment potentiometer 4M7. This circuit was...
We found this circuit in a Popular Electronics from the 90s. Its purpose is to monitor a power...
This configuration can be made based on other operational amplifiers. For other frequencies, the...