>There are two ways to dim LEDs: linear regulation and some sort of pulse modulation. Linear regulation is wasteful and you're pretty unlikely to encounter it,

>There are two ways to dim LEDs: linear regulation and some sort of pulse modulation. Linear regulation is wasteful and you're pretty unlikely to encounter it, especially in battery-powered devices such as phones or laptops. Pulse modulation is common. The other reason is LED brightness and color is quite non-linear with current, so PWM gives a much more straightforward dim than adjusting a current smoothly.