Favorite 68 Introduction LEDs are all around us: In our phones, our cars and even our homes. Any time something electronic lights up, there's a good chance that an LED is behind it. They come in a huge variety of sizes, shapes, and colors, but no matter what they look like they have one thing in common: they're the bacon of electronics.
Why would you drive an LED without a resistor? Simple, to make your circuit more energy efficient. Should you drive your LED with PWM set to a constant duty cycle (i.e. 5V PWM at 34% duty cycle to achieve an average voltage of 1.7V)? Yes and no.What is needed is a means to limit the current that flows through the LED. Resistors offer an expedient means for limiting the current through an LED to safe levels, but they have two downsides: 1. Resistors are inefficient: A resistor converts all the electrical energy it consumes into heat.
l1tuxm.