This very high input impedance JFET circuit was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. The JFET is a general-purpose transistor as is the output transistor.
We found this circuit in an English publication from 1980, but it can be assembled with BC548...
The circuit shown in the figure can generate signals of good intensity up to a frequency of 30...
This circuit was found in documentation from Analog Devices. The circuit is based on an AD795 and...