Schematics Calling Bell Circuit PCB | Electronic Circuits

Schematics Calling Bell Circuit PCB

Circuit
Apart from the normal musical calling bell circuits, this special electronic calling bell has been created to identify the sound even if there is noisy atmosphere. This bell circuit is not a typical Ding-Dong bell but has the capability of producing different sound that is very useful in noisy surroundings. By pressing a far away switch can trigger this circuit to work as a bell.


Circuit Diagram of Simple Calling Bell : Click  to enlarge

The circuit diagram shown in the figure has a multivibrator section formed by T2 and T3 BC 548 transistors. Since the oscillator hasn't the capability of driving a loudspeaker itself, a transsitor amplifier is provided. The supply voltage for this purpose is given through the collector of T1. Whenever the calling bell switch presses, C1 become fully charged and it drives the circuit. The voltage across the capacitor C1 controlls the sound output ,  the sound gets faded out  as discharge rate of capacitor.

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