| No | Part number | Description ( Function ) | Manufacturers | |
| 17 | UM66 | Music Calling Bell Musical Calling Bell By Kalyan Prodhan www.kalyan-prodhan.tk Connection Diagram Component List with cost (Approximate) Component Description (IC and Transistor) Precaution Modification for adaptation This is the simplest ever musical calling bell that can be easily built. It uses the musical 3 pin IC UM66 and a popularly known Transistor BC548b. The circui |
 ETC |
|
| 16 | UM6601 | PIN DIODE |
 Microsemi Corporation |
|
| 15 | UM6602 | PIN DIODE |
Microsemi Corporation |
|
| 14 | UM6606 | PIN DIODE |
Microsemi Corporation |
|
| 13 | UM6610 | PIN DIODE |
Microsemi Corporation |
|
| 12 | UM66T | Simple Melody Generator |
 Unicorn |
|
List of most widely used semiconductors
| Part Number | Function | Manufacturers | |
| 1N4007 | The 1N4007 is a rectification diode that is designed for high-voltage applications, typically up to 1000V. It has a maximum current rating of 1A and a forward voltage drop of around 0.7V. |
 Vishay |
|
| LM317 | This is a popular adjustable voltage regulator. |
 ON Semiconductor |
|
6N137 | LM393 | 2N3906 | 2N2222 | TIP120 | 1N5818 | LM324N | A1015 | SMAJ20CA |
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