Digital Electronic Door Buzzer Circuit Diagram

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This is a simple Digital Electronic Door Buzzer Circuit Diagram. Affordable simple door buzzers and buzzer systems for door entry security in homes, offices and buildings. When SI is depressed, an initial positive voltage is placed on C2 and the noninverting terminal of Ul. The circuit oscillates at a low frequency. As C2 charges up through R3, a rapid increase in frequency of oscillation results, producing (at SPKR1) a rapidly rising pitched sound. This sound is easily recognized over ambient noise. 


Digital Electronic Door Buzzer Circuit Diagram

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