An easy to assemble, good starter kit for new electronic enthusiasts. It plays a melody using the CMOS LSI chip UM66 which incorporates a 64-note ROM memory. The circuit includes an onboard voltage regulator and therefore can be supplied by a wide range of supplies from 1.5 to 12V DC.

The circuit can be used in two modes. In the first mode, the melody will play while the supply voltage is connected and will stop playing when it is disconnected. This mode of operation is ideal for applications such as alarms. In the second mode, the melody will play as long as the push button switch is held pressed and will stop playing when the push button switch is released. This mode of operation is ideal for applications such as a musical box.