UM66 IC comes in many different song melodies from which you can select your desired one. Each melody has a different code number written on the IC. More information of the codes can be found in the datasheet of the UM66 IC.
The circuit is not using any transformer and it is directly connected with the mains. The mains voltage passes through the two 5W 680 ohms resistors and rectified by the bridge of four 1N4007 diodes, which convert this AC voltage to DC. The 220uF capacitor filters the DC voltage, after filtration this voltage is fed to the UM66 melody circuit. An 8 ohms speaker is used at the output of the circuit, the wattage of the speaker can be any from 0.2 watt to 2 watt.
Note: Many points of this circuit are at AC mains voltage. It could give you lethal shock if you are not careful. If you don't know much about working with AC line voltages do not attempt to construct this circuit.
Here is an easy to build 220V AC doorbell using a UM66 melody IC. The circuit is quite simple and low cost one but provides very good results. The circuit can also be used for other purposes than doorbell for example calling bell etc. The output melody sound of the bell is very loud and can be heard in
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