This electronic bell circuit schematic is based on a specialized instrument melody generator , implemented by CMOS technology.
The heart of this circuit is the UM3481 IC which can be powered by a 1.5 volts battery and can be used for electronic doorbell , toys , melody clock , music box ,etc .
The UM3481 IC is designed to play the melody according to the previously programmed information and is capable of generating 16 songs with 3 instrument effects : piano, organ and mandolin.
UM3481 device has a pre-amplifier which provides a simple interface to the driver circuit.
Other features of the UM3481 dorbell circuit are : 8 beats selectable , low standby current , 3 timbres : piano, organ, and mandolin , up to 16 songs 5 tempos available through mask setting ,14 tones selectable .
The IC accepts a input voltage up to 5 volts but typically work powered by 1.5 volts . The speaker used in this door bell circuit project must have an 8 ohms impedance .
The transistor used can be replaced with similar types if you can not find 2sc9013, 2sc9012 type .