In this circuit, which uses only diodes, we have both simultaneous functions. The diodes are general-purpose types and the resistors have typical values of 2k2.
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...