This circuit was found in a Popular Electronics of the 90s. The operational amplifier admits equivalent and the phototransistor can be of any type.
This circuit was obtained in an old documentation, receiving the medium wave range. L1 has 20 + 60...
This circuit is from an old documentation from the 70s, so the transistors used are not common....
We found this circuit in a publication for radio amateurs of 1976. The operational amplifier is a...