This simple circuit has good gain and can be implemented with any general-purpose transistor. The circuit is from Electronics Now, June 1997. The coil determines the frequency range.
Found in an Electronics World of 1966, this circuit makes use of FETs of the time. Modern...
This setting that applies to any operational amplifier was found in an old documentation. For the indicated...
Applying an operational of the time, this circuit of an old documentation can be elaborated with modern...