With the configuration shown in the figure, we have the relay being activated when the microphone picks up a sound and shutdown when the X1 reset sensor is activated.
Found in an old Radio Electronics, this circuit uses common components today. The resistors of the IC...
This circuit was published in an article in Electronics Now magazine in October 1995. The circuit...
This DC-DC converter was found in old RCA documentation. The circuit operates at 15 kHz. The...