This alarm is either activated or triggered after a certain amount of time, giving the owner time to exit or enter and disarm it. The circuit is from a Radio Electronics from April 1975.
This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating...
This circuit was found in a 1987 magazine. It consists of an oscillator controlled by the...
This circuit was obtained in a 90s American documentation. The integrated circuit used is uncommon...