4017 Decade Counter Tutorial

History

The 4017 decade counter is a CMOS (Complementary Metal-Oxide-Semiconductor) integrated circuit that was introduced in the 1970s by Texas Instruments. It is part of the CD4000 series of ICs, which are widely used for various digital logic applications. The 4017 was designed to provide a simple and efficient way to count pulses and has been utilized in countless electronic projects since its inception.

Pin Configuration

The 4017 has a total of 10 outputs (Q0 to Q9) along with several control pins, including:

• Clock (CLK): The input signal used to advance the count.
• Reset (RST): Resets the counter to 0 when activated.
• Enable (EN): Activates or deactivates the counter.

Operation

The 4017 counter advances its output state with each clock pulse. It counts from 0 to 9, activating each output in sequence:

1. When the count is 0, Q0 is high.
2. After one clock pulse, Q1 goes high, and Q0 goes low.
3. This continues until Q9 is high after 9 pulses.
4. On the next pulse, the counter resets back to Q0.

Applications

The 4017 decade counter is used in various applications, including:

• LED Chasers: Sequentially lighting up LEDs for visual effects.
• Frequency Division: Dividing clock frequencies in digital circuits.
• Event Counting: Counting occurrences of events, such as button presses.

Sample Circuit

Below is a simple circuit diagram demonstrating the 4017 in an LED chaser configuration:

Figure: LED Chaser Circuit Using 4017 Decade Counter

In this circuit:

• The clock input is connected to a pulse generator.
• The outputs Q0 to Q9 are connected to individual LEDs through current-limiting resistors.
• Each LED lights up in sequence as the counter increments with each pulse.

Building the Circuit

To build a basic LED chaser circuit using the 4017, follow these steps:

1. Gather the following components:
   • 1 x 4017 Decade Counter IC
   • 10 x LEDs (different colors optional)
   • 10 x Resistors (220Ω)
   • 1 x 555 Timer (for pulse generation)
   • Breadboard and jumper wires
2. Connect the clock output of the 555 Timer to the CLK pin of the 4017.
3. Connect each LED to the outputs (Q0 to Q9) of the 4017, using a resistor in series with each LED.
4. Connect the RST pin to ground to avoid unwanted resets.
5. Power the circuit and adjust the frequency of the 555 Timer to see the LEDs chase.

Conclusion

The 4017 decade counter is a versatile and easy-to-use IC for counting applications. Its ability to drive multiple outputs makes it ideal for projects like LED chasers, event counters, and more. With its simple operation and clear pin configuration, it remains a favorite among hobbyists and engineers alike.