The Curious Case of Flickering (or Not!) and LEDs
1. Understanding LED Brightness Control
Ever wondered how those super-bright LEDs in your phone screen dim so smoothly without justpoofing out of existence? The secret weapon is often something called PWM, or Pulse Width Modulation. Think of it as a light switch that flips on and off REALLY fast. We’re talking thousands of times per second! This on-off switching controls the average amount of power delivered to the LED, which directly impacts its perceived brightness. Clever, right?
But why go to all this trouble? Why not just use a simple dimmer knob, like on an old lamp? Well, there are a few very good reasons, and they have to do with efficiency, color accuracy, and the overall lifespan of our glowing friends. Imagine trying to precisely control a river’s flow with a tiny valve; it’s fiddly and inefficient. PWM offers a more elegant, digital solution to the same problem.
So, imagine you have a light switch. You flip it on for a tiny fraction of a second, then off for a slightly longer fraction of a second. Repeat this process rapidly, and what do you get? A dimmed light! By varying the “on” time (the pulse width), we can precisely control how much light the LED emits. A wider pulse means more light, a narrower pulse means less. It’s like Morse code, but instead of communicating secrets, it’s controlling brightness!
And here’s the fun part: our eyes are generally too slow to perceive this rapid flickering. We see the average brightness, which appears perfectly smooth and continuous. Unless, of course, the PWM frequency is too low. Then you might start to notice some annoying flickering, especially when moving your eyes around. More on that later!