This circuit for incandescent lamps was found in the January 1980 Radio Elecronics magazine. The sensitivity can be controlled by a potentiometer and the microphone used is of the dynamic type.
This simple circuit produces pulses delayed in times set by the resistor in series with C on the...
Low power RF transistors such as the BF494 or BF495 and even those in the BC series can oscillate well...
This circuit is from a 1980s Signetics documentation. The circuit separates the modulation signal from a...