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