Music Generator circuit using IC UM66

UM66 melody generator is a simple and easy DIY project which is suitable for beginners and hobbyists. The circuit can be used as a doorbell, musical alarm, musical bell, etc.


The UM66 or also called as BT66 is a melody generator IC  which has 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. These are different versions of UM66 with various melody tone.

The UM66T19 IC with piano music “ Für Elise” is the most common and popular version of UM66.

UM66 IC Pinout

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

Pin1 Vcc
Pin2 GND
Pin3 Output

IC Um66 pinout, BC547 pin diagram

The transistor BC547 can be substituted with models such as BC546, BC548, BC549, 2N2222 or transistors with a similar rating.

um66 melody generator

The Um66 IC requires no any additional components for the generation of audio signals, it already has an inbuilt tone. The electrical signals of the corresponding notes of the melody tone will be generated at the output pin 3 of the Um66. The circuit is actually just converting the electrical signals to audio signals. The audio signal output is connected to the base of the transistor. The transistor amplifies the signals enough to drive a loudspeaker.

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

Components Required


Transistor – Q1- BC547

Resistor – R1- 100Ω


1 Response

  1. Thomas.m.p says:

    Interesting. Very good circuits and projects.

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