This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
The great advantage of the circuit shown in the figure is that its frequency is controlled by a...
This circuit can be used as a shield for microcontrollers. The circuit is from American...
Mounting an oscilloscope is the dream of many of our Internet users, although it comes up against...