We found this circuit in the December 1998 issue of Electronics Now magazine. RF transistors such as the BF494 or BF495 can be used. The circuit works at lower frequencies.
This circuit was obtained from the Radio Electronics magazine of October 1960. The circuit uses a...
Found in an Electronics World of 1966, this circuit makes use of FETs of the time. Modern...
Found in a 90s 303 Circuits, this circuit triggers a load from a 50 mV audio signal. When the...