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.
Suggested by General Electric in 1965 documentation, this circuit controls the current at a load...
Found in Popular Electronics from the 1980s, this circuit uses two operational amplifiers from...
We found this circuit in a Hands-on Electronics from 1985. The circuit is based on common...