This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based on a 741 that activates a buzzer with oscillator. R5 adjusts the sensitivity.
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...