The FETs of this circuit can be the BF245. The circuit is from an old documentation and can be used in the amplification of infrasonic waves, of a sonic attack, for example.
This circuit was found in an American publication called Ham Radio. The circuit uses still current...
From an audio signal, this circuit gets two signals of the same amplitude and opposite phases....
Found in an Electronic Design from 1968 this circuit generates a linear sawtooth signal modulated...