🐙 Why Do Leds Need Resistors

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. The main reason LEDs need resistors is to protect the LED from excessive current which can permanently damage the LED. LEDs have current ratings which indicate the optimal current at which the LED operates effectively. .

why do leds need resistors