This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit is based on a 555 and a MOSFET consisting of a flasher that controls a buzzer.
This circuit is from a Popular Electronics from the 90s. The integrated circuit admits equivalents...
This very interesting project was obtained in a 1980 publication. It consists of a device that is...
This circuit beeps when the sensor is triggered by the opening of the freezer door or other...