Simple And Practical Voice-Controlled Electronic Doorbell Circuit

Published:2011/8/4 0:35:00 Author:Robert | Keyword: Simple, Practical, Voice-Controlled, Electronic, Doorbell | From:SeekIC

If using this circuit as doorbell circuit, it needn't to install the button switch on the door. The visitors could just knock the door, and the doorbell would sound. The circuit is shown in the picture. The greatest feature of the circuit is using the loudspeaker as vibration input and also the doorbell sound output. The transistor V2, potentiometer KP and capacitor C2 make up the control circuit. The V1, V3, R2, C1 make up a complementary oscillator. When the switch S is closed and connected to the power, the power would charge the C2 through the C2, V2's BE junction and loudspeaker BL. The larger peak charging current make V2 saturated and conducted, which clamps the V3's collector polar's voltage level. After the C2's charging, the power would supply the base polar current for V2 through KP, thus it would maintain V2's critical saturation status and make the oscillator not work.



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