UM66 IC Melody Generator circuit

The given melody generator circuit is built with musical IC UM66. A melody generator using um66 is very inexpensive and simple to assemble. The circuit can be used as a doorbell, musical alarm, musical bell, etc or for any type of music circuit projects.

um66 IC

The UM66 or also called as BT66 is a melody generator IC with an inbuilt melodic tone. It’s very hard to find an equivalent or alternative IC for Um66. But a number of models such as UM66T09S, UM66T11L, UM66T11S, UM66T13L, UM66T13S,…, UM66TXXS are available versions of UM66 with various melody tone. The UM66T19 IC with piano music “ Für Elise” is the most common and popular version of UM66.

IC Um66 is a 3 pin device with a TO-92 package which makes it look similar to a transistor.

UM66 IC Pinout

Pin1 Vcc
Pin2 GND
Pin3 Output

IC Um66 pinout, BC547 pin diagram

The main part of this circuit diagram is IC UM66 and the transistor BC547.

um66 melody generator

In the circuit, transistor models such as BC546, BC548, BC549, 2N2222 or transistors similar in rating can be used as an alternative for BC547.

The Um66 IC requires no any additional components for the generation of audio signals. The electrical signals for the corresponding notes of the melody tone are generated at the output pin 3 of the Um66. The audio signal output has connected to the base of the transistor. Here the transistor is used for the amplification purpose to enhance the signals enough to drive a loudspeaker. The circuit is actually just converting the electrical signals to audio signals.

The IC Um66 has an operating voltage range of 1.5V to 4.5V. So a 3V battery is enough to operate the circuit. Also, as the IC UM66 has built with CMOS technology, its power consumption is extremely low.

Components Required


Transistor – Q1- BC547

Resistor – R1- 100Ω


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