This circuit was obtained from a Radio Electronics from the 90's. The circuit limits the strength of an audio signal preventing saturation. Equivalent operational amplifiers can be tried.
The circuit shown has a voltage gain of 500 times and can use equivalent FETs like the BF245. The...
Found in a 1968 Novel Electronics Circuit, this circuit compares two light intensities using...
We found this circuit in an old publication from Argentina. The relay must be of the sensitive type,...