How does PWM control LED brightness or motor speed?
Let’s dive into how PWM (Pulse Width Modulation) actually makes an LED look dimmer or a motor run slower — even though the voltage is always “full ON” or “full OFF.” Principle of PWM PWM rapidly switches voltage ON and OFF at a fixed frequency. The duty cycle (%) controls the ratio of ON-time to OFF-time in each cycle. The load (LED, motor, etc.) responds to the average power delivered, not the instantaneous ON/OFF states. So, instead of lowering voltage directly, PWM delivers “packets of full power” and lets the load integrate them. LED Brightness Control Human eyes cannot perceive fast flickering above ~100 Hz → instead, they see the average light output . Example: 10% duty cycle → LED is ON only 10% of the time → appears dim. 50% duty cycle → LED is ON half the time → medium brightness. 90% duty cycle → LED almost always ON → near full brightness. Advantage: LED always gets correct forward voltage → no color shift ...