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The emergence of solid-state lighting is adding

Lutron Electronics—changed the lighting control

heat to the topic of lighting controls. Energy

landscape by making it practical and affordable

codes, advances in wireless communication,

beyond theatrical use.

intelligent networking and computer interface software are fueling imaginations, while energy

85 IQ – Getting to Practically 'Dim'

cost escalation is exciting customer interest.

In the late 1950s, the first solid-state dimmer

Unfortunately, much of the potential from this op-

design for incandescent lamps, developed by GE,

portunity is locked up by proprietary approaches

utilized thyristors or silicon-controlled rectifiers

at odds with the diversity of lighting products

to cut portions of the AC sine wave supplied to

necessary to complete projects. Making matters

the light source. This helped reduce light output.

worse are some marketers promoting simple,

A short time later, TRIAC—Triode for Alternating

automatic controls as “smart” further confusing

Current—devices offered lower cost and greater

customers. So it begs the question, just how intel-

durability. Since incandescent lamps suffer only

ligent is solid-state lighting today? Following is a

minor issues with wave cut dimming—some fila-

review of what's out there and the corresponding

ments will sing or flicker a little—this technology

intelligence quota.

delivered economy and compact size ideal for wall-box dimmer use. This remains the standard

65 IQ – Immature and Intellectually Challenged

for incandescent dimming today.

Lighting control has been a part of lighting from

The introduction of more complex light

the installation of the first electric lamp. The ba-

sources, such as low-voltage and discharge sourc-

sic use of on/off switches and contactor controls

es, e.g. fluorescent and HID, presented dynamics

were an early selling feature, eliminating snuffing

beyond the capability of TRIAC dimmers. For

gas or oil flames one fixture at a time. At this

inductive loads, MOSFET—Field Effects Transistor

level, little has changed since 1897.

dimmers, which create trailing edge wave cutting,

Dimming emerged as a means to balance and

vs. leading edge for TRIAC—produced acceptable

tune stage lighting. Early forms of the dimmer

results. For ballasted products, however, which

were simple resisters put in series with the lamps,

incorporate starters and lamp current controls

the former consuming as much or more energy

circuitry, special approaches became necessary.

as the loads being controlled. The equipment, too,

This led to the development of two architectures

was too bulky for wide spread use. While early

still in use today: Three wire and 0—10V control.

efforts were hobbled by the technology of the

In the case of the former, power supplied to the

day, the invention of the solid-state dimmer by

light source remains uncontrolled, and a separate

Joel Spira in 1959—who later went on to found

“signal” wire at line voltage is used to communicate


Architectural SSL - January 2013  

Chronicling the Advancement of LED and Solid-State Lighting in the Built Environment.

Architectural SSL - January 2013  

Chronicling the Advancement of LED and Solid-State Lighting in the Built Environment.