Introduction
The CD4017 decade counter can be used to count pulses from a clock source, and in this experiment, we will use a 555 timer configured in astable mode to provide the clock signal. The output of the CD4017 will light up a series of LEDs in response to the clock pulses.
Objective
The objective of this experiment is to demonstrate how to use a 555 timer as a clock source for the CD4017 decade counter to sequentially light up LEDs.
Components Needed
- 1 x CD4017 Decade Counter IC
- 1 x 555 Timer IC
- 10 x LEDs (different colors)
- 10 x Resistors (220Ω for each LED)
- 2 x Resistors (10kΩ and 1kΩ for the 555 timer)
- 1 x Capacitor (10µF for the 555 timer)
- 1 x Breadboard
- Connecting Wires
- Power Supply (5V)
Circuit Diagram
Procedure
- Connect pin 1 (GND) of the CD4017 to the ground of the power supply.
- Connect pin 11 (VCC) of the CD4017 to the positive voltage supply (5V).
- Connect the output pins (Q0 to Q9) of the CD4017 to the anodes of the LEDs. Connect the cathodes of the LEDs to ground through a 220Ω resistor.
- Connect the 555 timer in astable mode to generate clock pulses:
- Connect pin 1 (GND) to ground and pin 8 (VCC) to 5V.
- Connect pin 2 (TRIG) to pin 6 (THRESH).
- Connect a resistor (10kΩ) between pin 7 (DISCH) and VCC.
- Connect another resistor (1kΩ) between pin 7 (DISCH) and pin 6 (THRESH).
- Connect a capacitor (10µF) between pin 6 (THRESH) and GND.
- Connect the output (pin 3) of the 555 timer to the clock input (pin 14) of the CD4017.
- Power the circuit. The LEDs will light up sequentially in response to the clock pulses generated by the 555 timer.
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Results
The LEDs should light up one after another, creating a chaser effect as a result of the clock pulses from the 555 timer. The speed of the LED chaser effect can be adjusted by changing the resistor and capacitor values in the 555 timer circuit.
Conclusion
In this experiment, we successfully used a 555 timer as a clock source for the CD4017 decade counter. This setup demonstrates how to integrate different ICs to achieve desired outputs, such as creating a sequential LED chaser effect.
