This circuit is for simple Random LED Number Generator Circuit using IC CD4017 decade counter and IC CD4011 NAND gate.
It works on 9V power supply and the LEDs in the circuit represent the numbers.
When we press the switch, one LED remains ON, because the counter runs very fast and the final LED looks random.
Therefore, this circuit works like an electronic dice which is simple to build and is useful for games, school projects and learning digital electronics.
Circuit Working:
Parts List:
| Components | Specification | Quantity |
|---|---|---|
| Resistor | 1k 1/4 watt | 2 |
| Capacitor | Electrolytic 4.7uF 25V or higher | 1 |
| Semiconductors | IC CD4017 Decade Counter | 1 |
| IC CD4011 Quad NAND Gate | 1 | |
| LED 5mm any color | 10 | |
| Push Button Switch | 1 | |
| Power Supply 9V Battery or 9V DC Adapter | 1 |
At first, when power supply 9V is given the IC CD4011 then NAND gate starts working.
Two NAND gates are connected as astable multivibrator and therefore, it produces continuous clock pulses, the speed of pulses depends on resistor R1 and capacitor C1.
If R1 value increases then the speed becomes slow and similarly if C1 increases then delay becomes more.
Now these clock pulses go to pin 14 of CD4017 and this CD4017 is decade counter IC which has 10 outputs from Q0 to Q9.
Initially, Q0 becomes HIGH then first LED turns ON and when next clock pulse comes, Q1 becomes HIGH and previous output becomes LOW.
As a result, second LED turns ON and in the same way the LEDs glow one by one from LED1 to LED10.
After Q9 the counter resets automatically to Q0 and thus the cycle repeats continuously.
Reset pin is connected properly so counting remains from 0 to 9 and therefore, smooth chasing effect is obtained.
How to Build:
To build a Random LED Number Generator Circuit following are the steps we require for connection:
- Start, the circuit first by gathering all the circuit parts.
- Then start with IC1 CD4017 and connect pin 16 to +9V power supply.
- Pin 8, 13 and 15 connect to GND.
- Pin 14 clock input pin is connected to one end of switch S1.
- Output Pins for LEDs:
- Pin 3 – Q0 – LED1.
- Pin 2 – Q1 – LED2
- Pin 4 – Q2 – LED3
- Pin 7 – Q3 – LED4
- Pin 10 – Q4 – LED5
- Pin 1 – Q5 – LED6
- Pin 5 – Q6 – LED7
- Pin 6 – Q7 – LED8
- Pin 9 – Q8 – LED9
- Pin 11 – Q9 – LED10
- Each LED anode is connected to the respective output pin of IC4017.
- The cathode of each LED is connected to ground through resistor R2.
- IC2 CD4011 pin 14 is connected to +9V power supply.
- Pin 7 is connected to GND. In the first NAND gate, pin 1 and pin 2 are inputs and pin 3 is the output.
- In the second NAND gate, pin 5 and pin 6 are inputs and pin 4 is the output.
- Pin 4 is connected to the positive terminal of capacitor C1.
- Resistor R1 and capacitor C1 are connected between output and input to create oscillation.
- Lastly, S1 is a push button switch used for reset or start control as per the circuit design.
Conclusion:
This Random LED Number Generator Circuit is simple and low cost project.
It uses very common ICs and therefore, it is best for beginners and students.
Also, circuit is easy to build on breadboard and by changing resistor or capacitor value the speed can be adjusted easily.
Finally, this project helps to understand counters and oscillators clearly and so it is good basic electronics learning project.
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