PWM (Pulse Width Modulation) at different framerates - 31/05/2025

PWM is a technique used to make an LED "appear" dimmer to the human eye.

It does this by turning the LED off and on many times in a split second. This gives the illusion that is is dimmer, however in reality it is just turned off 50% of the time.

When recording PWM at different frame rates, we see different results.

For example, see the LED on my heater which uses PWM.

A green lights on a black background AI-generated content may be incorrect.

240fps

---------------------------------------------------

A black device with green lights AI-generated content may be incorrect.

120fps

---------------------------------------------------

A black rectangular object with green lights AI-generated content may be incorrect.

60fps

---------------------------------------------------

A close up of a machine AI-generated content may be incorrect.

30fps

---------------------------------------------------

A digital clock with green numbers AI-generated content may be incorrect.

24fps

---------------------------------------------------

 

As you can see, at 24fps the numbers look normal. As we increase the fps, you can see how the PWM is in effect.

Side note: the reason that the videos at higher fps are darker is because the camera shutter speed has less time to capture light.

Thank you for reading until the end! I hope you enjoyed it! If you have any questions or comments, don't hesitate to contact me at makrypodisc@hotmail.com