This damped oscillator that mimics the sound of a gong was found in 90s American documentation. The circuit signal must be applied to an external amplifier.
Suggested by a Popular Electronics, this small amplifier that has a detector to follow RF...
We found this circuit in the November 1992 Radio Electronics magazine. The circuit uses an LDR as a...
We found this circuit in the March 1995 issue of Electronics Now magazine. The circuit has a...