Calling Bell

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This is a very simple circuit consisting of only two components,  a three pin ic UM66 or BT66 and a transistor BC548. this is a very easy method to make a calling bell. the circuit can be made without soldering also. i used a cassette box as outer covering    

Step 1: Parts List

1 x UM66
1 x BC548
1 x speaker 8ohm
2 x AA size battery
1 x battery holder
1 x common circuit board

Step 2: Circuit Diagram

complete the circuit according to the circuit diagram, its very simple circuit and works on two AA batteries, the music will vary according to the IC UM66   

Step 3: Conclusion

hope you enjoy the circuit................ please rate the instructable and comment if there is any doubts.Rechargeable battery should not be used if Speaker resistance is less than 8 Ohm and may burn the Transistor BC548 

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    5 Discussions

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    Dipankar

    5 years ago on Introduction

    It is a very good project specially for patients in bed who requires constant attention.

    1 reply
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    vishalapr

    7 years ago on Introduction

    This is so cool and cheap!Just the kind of project I like!
    Have a look at my ibles!!!