Introduction

An LED Chaser circuit is an electronic project in which multiple LEDs turn ON and OFF in a sequential pattern, creating a running or chasing light effect. This project is widely used for decorative lighting, signboards, and learning digital electronics concepts.

The LED chaser helps beginners understand timing, sequencing, and output control.

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Objective of the Project

The main objectives of this project are:

• To create a running light effect using LEDs.
• To understand sequential switching.
• To learn timer and counter concepts.
• To design a visually attractive electronic circuit.

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Working Principle

The LED chaser works by generating timing pulses and shifting them across multiple outputs.

Using 555 Timer + 4017 Counter

1. The 555 timer generates clock pulses.
2. These pulses are fed to the 4017 decade counter.
3. The 4017 activates one output at a time.
4. LEDs connected to each output glow sequentially.

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Components Required

Basic LED Chaser Circuit

• IC 555 Timer
• IC 4017 Decade Counter
• LEDs (8–10)
• Resistors (220Ω)
• Capacitor (10µF – 100µF)
• Potentiometer (100kΩ)
• Power Supply (5V–12V)
• Breadboard & wires

Arduino-Based LED Chaser

• Arduino Uno
• LEDs
• Resistors
• Jumper wires

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Circuit Diagram

555 + 4017 Based Circuit

555 Timer (Astable Mode)
        |
     Clock Pulses
        |
     4017 Counter
        |
     LEDs (Sequential)

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Arduino-Based Circuit

LEDs ---- Arduino D2–D9 (via 220Ω resistors)
GND ----- Common Ground

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Arduino Code (Optional)

int leds[] = {2,3,4,5,6,7,8,9};
int total = 8;

void setup() {
  for (int i = 0; i < total; i++) {
    pinMode(leds[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < total; i++) {
    digitalWrite(leds[i], HIGH);
    delay(200);
    digitalWrite(leds[i], LOW);
  }
}

Code Explanation

• LEDs are connected to digital pins.
• Each LED turns ON one by one.
• Delay controls the chasing speed.
• Speed can be modified by changing delay value.

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Advantages

• Simple and attractive design
• Easy to understand
• Low cost
• Useful for learning sequencing

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Applications

• Decorative lighting
• Advertising boards
• Signal indicators
• Educational demonstrations

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Conclusion

The LED Chaser circuit is a fun and educational project that introduces timing and sequencing in electronics. It is suitable for beginners and can be expanded with bidirectional chasing, speed control, or music synchronization.