LED Chaser Circuit Using CD4017 IC (Rainbow Star)
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✨Create a Stunning Rainbow LED Star Effect with Just a Few Components!
Looking to bring your LED projects to life with color and motion? The LED Chaser Circuit using the CD4017 IC (Rainbow Star) is a visually captivating and beginner-friendly electronics project that creates a rotating rainbow light effect—ideal for decorations, holiday displays, or tech-inspired art.
Using a CD4017 decade counter and a 555 timer IC, you can sequence 10 colorful LEDs in a circular or star pattern. Each LED lights up one after the other, giving the illusion of a spinning or “chasing” rainbow. This circuit mimics the classic “Knight Rider” or running marquee light—now enhanced with a rainbow aesthetic.
Materials for the Project
1. 10k resistor ×1
2. 10uf 50v capacitor ×1
4. 104 Ceramic capacitor ×1
5. CD4017 ic ×1
6. NE555 ic ×1
7. 3mm Blue LED × 60
8. Brass Wire ×1
How It Works
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The 555 timer is set up in astable mode, sending continuous clock pulses to the CD4017.
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Each clock pulse advances the output of the CD4017 IC from Q0 to Q9.
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Each output (Q0–Q9) lights up one LED at a time—creating a chasing effect.
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After Q9, it resets and starts again from Q0.
| Pin | Name | Function |
|---|---|---|
| 1 | Q5 | Output 5 (6th LED) |
| 2 | Q1 | Output 1 (2nd LED) |
| 3 | Q0 | Output 0 (1st LED) |
| 4 | Q2 | Output 2 (3rd LED) |
| 5 | Q6 | Output 6 (7th LED) |
| 6 | Q7 | Output 7 (8th LED) |
| 7 | Q3 | Output 3 (4th LED) |
| 8 | GND | Ground (0V) |
| 9 | Q8 | Output 8 (9th LED) |
| 10 | Q4 | Output 4 (5th LED) |
| 11 | Q9 | Output 9 (10th LED) |
| 12 | Carry Out | Use to cascade with another CD4017 |
| 13 | Disable | Active HIGH → stops counting (tie to GND to enable) |
| 14 | Clock | Receives clock pulses (from 555 Timer) |
| 15 | Reset | Active HIGH → resets count to Q0 (tie to GND for normal) |
| 16 | Vcc | Power supply (3V–15V, typically 5V–9V) |
Download Circuit Diagram
Final Thoughts
The LED Chaser Circuit using the CD4017 IC is more than just a fun visual project—it’s a fantastic way to learn about digital logic, timing circuits, and sequential control in electronics. Whether you arrange the LEDs in a star pattern, circle, or wave, the colorful “rainbow” motion effect can turn any simple display into something vibrant and dynamic.
This project is
✅ Perfect for beginners and students
✅ Great for school fairs, decorations, or cosplay props
✅ Easily customizable in color, speed, and shape
✅Expandable—cascade multiple CD4017s for longer sequences
So whether you’re building your first circuit or adding flair to an art piece, this Rainbow Star LED Chaser will spark both light and creativity.