Illuminate Your Creativity: DIY LED Chaser with 555 Timer and 4017 Counter for Mesmerizing Light Displays

A unique electronic project, the LED Chaser circuit makes use of the well-known 555 timer and 4017 decade counter IC. These integrated circuits are used in this project to produce an eye-catching series of LED lights that seem to chase one another in a sequential pattern. The 4017 counter divides the steady clock signal produced by the 555 timer, which acts as an astable multivibrator, to gradually turn on each LED.

The astable mode of the 555 timer integrated circuit generates a continuous square wave output. The 4017 decade counter uses this square wave as a clock signal. An incoming clock signal can be divided into 10 distinct outputs by the 4017, a flexible counter/divider integrated circuit. These outputs are connected to individual LEDs in the LED chaser circuit, which produces an amazing chasing effect as the LEDs glow one after the other.

By changing the resistor and capacitor values in the 555 timer circuit, the LED chaser’s speed can be changed. Additionally, by connecting the 4017 outputs in various configurations, the LED chase’s pattern and direction may be changed.

In addition to giving students a practical introduction to the concepts of timing and sequencing in electronic circuits, this project produces an eye-catching end product that may be used for displays or educational purposes. Electronics hobbyists and beginners can explore the capabilities of these integrated circuits while assembling an eye-catching light display by assembling the LED Chaser using the 555 Timer and 4017 Counter.

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Led chaser using 555 timer and 4017

Circuit Schematic

Led chaser using 555 timer


  • CD4017 Counter
  • 555 Timer
  • LEDs
  • 10 KΩ Resistor
  • 10 KΩ Variable Resistor
  • 10 μF/25V Capacitor
  • 10 nF Capacitor
  • 9V Battery
  • Breadboard

Circuit Connection of Led Chaser

The IC 555 timer can be used as an astable multivibrator in the led chaser circuit shown above, and its output pin 3 is linked to the 4017 IC’s clock input.

The resistors R1 (10 KΩ), R2 (10 KΩ pot), and capacitor C1 (10 uF/25V) set the output frequency of the 555 timers.

Pins 8 and 1 of the VCC and ground respectively are linked to the power source.
Since pin 5 of the control voltage is not in use, we are connecting a capacitor, C2 (10 nF), to the ground in order to prevent high-frequency noise.

Similarly, the CD4017 IC’s VDD pin 16 and VSS pin 8 are directly connected to the power source.

Since pin 13 of the clock is an active low input, it is linked to the ground. The output of the 555 timer pin 3 is connected to clock input pin 14. LEDs are linked to each decoded output pin (Q0 through Q11).

Working Principle of Led Chaser

555 timers are utilised to create an astable multivibrator in the chaser circuit, as I previously demonstrated. Thus, the square wave output from the 555 timer IC acts as the CD4017 IC’s clock pulse.

The clock input pin 14 of the 4017 IC is directly connected to the pulsing output of the timer IC. 10 output pins are present on this counter IC.

The current output is turned off and the following sequential output is turned on each time the clock input detects a voltage. This explains why it appears like the LEDs are chasing one another.

The following formula provides the 555 timer IC’s output frequency.

Output Frequency = 1.44/((R1 + 2R2) * C1)

By adjusting the variable resistance R2, we can simply change the LED chaser circuit’s output frequency. It regulates the speed at which the LEDs chase.

Applications of Led Chaser

  • Create eye-catching decorative lighting displays for parties, events, or home decor.
  • Design a festive LED chaser for Christmas decorations, adding a dynamic element to your holiday lighting.
  • Simulate a traffic signal with LEDs changing in sequence, helping to educate or entertain.
  • Replicate the iconic “Knight Rider” car scanner effect by moving LEDs back and forth in a sweeping motion.
  • Connect the LED chaser to the audio input to create a visual representation of sound levels, making a simple audio level indicator.

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