Electronic Door Buzzer

Inside:: Doorbell Circuits / Other Circuits

When SI is depressed, an initial positive voltage is placed on C2 and the noninverting terminal of Ul. The circuit o

scillates 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.

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