This circuit, from the 70's, can be assembled with a more modern FET like the BF245. The circuit is powered by a 9 V battery, as its consumption is very low.
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...