This is fun project for small Christmas Music Box Circuit using IC UM66.
UM66 chip already has melody inside.
When power ON, it plays Christmas notes.
It is good for greeting cards, toys and mini gifts.
Circuit Working:
Parts List:
| Part Name | Value | Quantity |
|---|---|---|
| Resistor | 4.7k 1/4 watt | 1 |
| Capacitor | Electrolytic 1uF 25V | 1 |
| Semiconductors | IC UM66 | 1 |
| Transistor BC547 | 1 | |
| Speaker 4 to 8 ohms | 1 | |
| Battery 3V | 1 |
Main brain of this circuit is IC UM66.
UM66 makes melody when power is ON.
Its output is weak, so transistor makes it strong.
Transistor drives the small speaker.
Resistor controls base current.
Capacitor keeps supply smooth.
Speaker plays the Christmas tune.
Below is the list of Christmas melodies commonly found in UM66T-XX series melody ICs.
UM66T19 – Jingle Bells
UM66T20 – We Wish You a Merry Christmas
UM66T21 – Silent Night
UM66T22 – Santa Claus Is Coming to Town
UM66T23 – Joy to the World
UM66T24 – O Christmas Tree
UM66T25 – Rudolph the Red-Nosed Reindeer
UM66T26 – Little Town of Bethlehem
UM66T27 – O Come All Ye Faithful
UM66T28 – The First Noel
Note:
Different manufacturers sometimes use slightly different tune numbers.
But the above list is the most widely used set for Christmas UM66T series.
How to Build:
Below are the steps to build a Christmas Music Box Circuit using IC UM66:
- Collect all parts shown in circuit above.
- Pin 3 goes to transistor base through resistor R1.
- Pin 2 of UM66 goes to 3V positive.
- Pin 1 goes to ground.
- Emitter of transistor goes to ground.
- Speaker one side goes to transistor collector.
- Other side of speaker goes to positive.
- C1 capacitor goes between positive and ground.
- Add switch in battery line for ON and OFF.