See the Signal. Microcontrollers like Arduino cannot output a varying analog voltage; they can only output 0V or 5V. To solve this, we use Pulse Width Modulation (PWM). By flickering the pin on and off thousands of times per second, we create an “average” voltage. This lab visualizes that square wave—the wider the “pulse,” the more power is delivered.

PWM Lab Visualizer

PWM Visualizer

Analyze Pulse Width & Duty Cycle

Duty Cycle (%) 50%
10ms Time ON
2.5V Avg. Voltage (5V Ref)
Intro: Pulse Width Modulation (PWM) is a technique for getting analog results with digital means. By switching a digital signal between HIGH and LOW extremely fast, we can control the average power delivered to a device.

Footer: In this simulation, we assume a standard 5V reference. A 50% duty cycle means the signal is ON for half the time and OFF for the other half, resulting in an effective 2.5V output.

Lab Notes:

  • Duty Cycle: The percentage of time the signal is HIGH during one period. 0% is always OFF, 100% is always ON.
  • Effective Voltage: Calculated as Vout​=Vref​×DutyCycle.
  • Common Uses: LED dimming, DC motor speed control (H-Bridge), and Servo motor positioning.

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