This configuration was found in an English magazine from 1965. It is valid for any junction FET. The input impedance is 5.5 M ohm higher than conventional stages.
Found in National Semiconductor documentation from the 90's this circuit uses a piezoelectric sensor....
This is one of the channels of an amplifier suggested by Westinghouse in 1970s documentation. The circuit...
This circuit measures the RF power of oscillators and small transmitters in the range of 0.05 to...