This circuit was found in the April 1973 issue of Radio Electronics magazine. Using TTL technology, it was recommended for vehicles of the time. The circuit was connected to the contact breaker.
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...