There are two ways to control the LED brightness. Current through the LED is a kind of change, general LED tube allows continuous working current is controlled in 20 ma, in addition to the red leds have saturation phenomenon, other

The LED brightness basically proportional to the flow of electric current; Another method is to use human eye visual inertia, using pulse width modulation method to realize gray scale control, which is periodic change light pulse width (namely the duty

Ratio), as long as the repetition of the light cycle is short enough (that is, the refresh rate is high enough), the human eye is feeling less than glowing pixels in jitter. Due to the pulse width modulation is more suitable for digital control, so in general

Use computer to provide the LED Screen content today, almost all the LED screen is controlled by pulse width modulation to grayscale.