CIPAD 30: Comment réaliser un générateur d'ondes carrées à fréquence variable dans TinkerCad

Introduction

In this tutorial, we will learn how to build a variable frequency square wave generator using TinkerCAD. This project is essential for the upcoming lesson, where we will create a frequency counter that displays the generated frequencies on an LCD screen. Understanding this generator will also provide valuable insights into the functioning of the 555 timer.

Step 1: Set Up TinkerCAD

• Create an Account: If you don’t have a TinkerCAD account, visit TinkerCAD and sign up for free.
• Start a New Project: Once logged in, click on "Create New Circuit" to begin your project.

Step 2: Gather Components

You will need the following components for this project:

• 555 Timer IC
• Resistors: 1kΩ and a potentiometer (variable resistor)
• Capacitor: 10µF
• Breadboard
• Wires
• Power supply (5V)

Step 3: Place the 555 Timer on the Breadboard

• Identify Pins: The 555 Timer has 8 pins. Familiarize yourself with their functions:

  • Pin 1: Ground
  • Pin 2: Trigger
  • Pin 3: Output
  • Pin 4: Reset
  • Pin 5: Control Voltage
  • Pin 6: Threshold
  • Pin 7: Discharge
  • Pin 8: Supply Voltage

• Insert the 555 Timer: Place the 555 Timer IC on the breadboard, leaving space around it for connections.

Step 4: Connect the Components

1. Connect Power:

   • Connect Pin 1 (Ground) to the ground rail of the breadboard.
   • Connect Pin 8 (Supply Voltage) to the positive rail (5V).

2. Add Resistors:

   • Connect a 1kΩ resistor from Pin 7 (Discharge) to Pin 8 (Supply Voltage).
   • Connect the potentiometer between Pin 7 (Discharge) and Pin 6 (Threshold).

3. Capacitor Connection:

   • Connect the 10µF capacitor from Pin 6 (Threshold) to ground.

4. Trigger and Output:

   • Connect Pin 2 (Trigger) to Pin 6 (Threshold).
   • Connect Pin 3 (Output) to where you want to measure the output frequency.

Step 5: Adjust Frequency

• Using the Potentiometer: Turn the potentiometer to change the resistance, which will vary the frequency of the square wave generated. This is a key feature of the circuit, allowing for frequency modulation.

Step 6: Test the Circuit

• Power the Circuit: Connect the power supply and observe the output on an oscilloscope or a frequency counter to verify that the square wave is being generated correctly.
• Adjust and Observe: Adjust the potentiometer and watch how the frequency changes.

Conclusion

In this tutorial, we successfully built a variable frequency square wave generator using TinkerCAD and learned about the essential components involved. The next step will be to create a frequency counter that can display the frequencies produced by our generator. Be sure to experiment with different resistor and capacitor values to see how they affect the output frequency. Happy tinkering!