This step of good gain was obtained in an American publication of the 1980s. The circuit can be powered by voltages from 3 to 9 V and the FET can be of almost any type.
This circuit uses an unusual electromechanical component: a mechanical blade resonator. The...
This circuit from a Japanese publication in 1968 uses germanium transistors from the time like the...
Found in a 90s Electronic Design, this circuit can provide a relatively high-power output. The basic...