This resistance meter was found in an English documentation from 1989. The operational amplifier admits an equivalent and the transistor can be a BC558 or BC559.
The integrated circuit used in this configuration for noise reduction on FM radios is not common...
This circuit was found in the April 1984 issue of Radio Electronics magazine. The integrated...
We found this circuit in a 1977 National Semiconductor Databook. The circuit can use other FETs...