Manholes full-color unit board price, led unit board the wholesale more three-in-one unit board supply the best in Holley flag unit board factory, the Company has been committed to the research and development of photovoltaic industry, there are two methods to control LED brightness. One is to change flow through the LED current, the general LED pipe allows a continuous working current is about 20 mA, in addition to the red LED, other LED brightness is substantially proportional with the current flowing into saturation phenomenon; Another method is to use human visual inert, grayscale control with pulse width modulation method, is the cyclical changes in the optical pulse width (duty cycle), as long as this repeating cycle of light is short enough (ie, the refresh rate is high enough), people The eye is to feel light-emitting pixel in jitter. Since the pulse width modulation is more suitable for digital control, so commonly used by the microcomputer to provide LED displays today, almost all of the LED screen using pulse width modulation to control the gradation level.