Originally developed for incandescent lighting, analog dimming controls the current fed by the driver to the LEDs, i.e., full current equals full brightness.
LED Dimming Options
Dimmable LED systems require a dimming driver that both converts the main’s AC supply and raises and lowers the amount of electrical energy flowing to the LEDs.
Control devices (rotary knob, a slider, wireless interface) send electrical signals to the dimming driver which controls to what extent the LED arrays will dim based on common dimming protocols
In leading edge phase cut dimming (also known as standard or forward phase dimming) the leading section of upper and lower sinewave is chopped, or ‘cut’. While this is a cheap, simple, and widely available technology, it often has unwanted side-effects, i.e.humming, buzzing, and flicker.
In trailing edge phase cut or reverse phase dimming the trailing section of the sinewave is chopped, or ‘cut’. The side-effects for trailing edge dimming are lessened.
Take note: The “chopping” effect in phase cut dimming happens at 60 cycles per second. While most individuals will not see it, occupants with Autism, Irlen’s Disease, phoria or other sensory abnormalities may ‘see’ or perceive flicker at 60 cycles per second. Installing contractors should discuss the visual needs of occupants with customers, administrators and facility managers.
Analog dimming has appeal to installers and contractors. While analog and 0-10VDC systems may require low voltage Class 2 control wiring connecting the control device to the purple and gray leads on the driver, installation is simple for new construction. Existing construction and lighting retrofits may require wireless installations, depending on cost.
A hard-wired dimming system, once installed and commissioned, provides confidence and security for both the contractor and the end-user. Wireless systems may cause concern due to complexity, set-up, scheduling, sensitivity and the demands of the environment.
