Technical Corner: Understanding 1-10V LED Dimming
The majority of commercial dimmable LED luminaires use the 0-10V reference voltage dimming system. Commercial dimmable LED drivers respond to dimming control from 1-10 volts. This means the LEDs will only vary brightness for ranges from 10 to 100% of power output. For values below 10% of power the LEDs go to the full darkness "OFF" state. This requires that the dimming system be compatible with DC 1-10V protocol and all fixtures that are to be controlled together have the purple and gray leads in the fixture interconnected. This means that separate control wiring has to be run to each fixture. This system is not compatible with line voltage dimmers.
The chart below shows the relationship of the 0-10V reference dimming voltage to the power output and perceived light level output of the fixture.
LED Dimming Characteristics
The perceived light level is higher than the actual power level. This attribute causes it to seem brighter than the power output level and the lowest level will be greater than 10%. Often occupants will perceive the lowest level to be between 15 and 20%. It is important to take this effect into consideration for projects that need very low levels at the bottom of the range such as churches and theaters. Standard commercial 1-10V dimming drivers cannot provide low level dimming for these applications.