We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
In the figure we have a circuit with two operational amplifiers 741 capable of doubling the...
What differentiates this circuit from the previous one is the need for a much smaller current to...
This circuit was obtained in a Maxim documentation from the 90's. The circuit applies to...