THE FATHER OF
Lighting magazine celebrates the extraordinary man
WORDS: Ray Molony
who changed the ambience in homes and buildings
all over the world when he invented the solid-state
dimmer and urged us to ‘dial romance’…
It was only the size of a pea in the palm of his hand, but the former US Navy sailor was fascinated. A decade earlier, during World War II, Joel Spira had received a highly classified briefing on a similar device used in a radar triggering mechanism. It made the deployment
of secret radars faster and easier. That unit, however,
had been the size of a carton of milk. This was tiny.
Called a ‘silicon-controlled rectifier’, it was small, and
efficient, and it worked in a novel way.
It reduced electrical power in a circuit not by the
conventional method of dissipating the heat in a
resistive copper coil of a rheostat or autotransformer,
but by ‘chopping’ the 60-hertz electrical sine wave so
there was very little heat dissipated in the controller
itself. To the 33-year-old Spira, who had graduated with
a physics degree from Purdue University in Indiana
after demob, the possibilities of the innovation were
endless. But one application stood out above all others.
What if the device could be used to dim lighting?
At the time he and his wife, Ruth, were living in an
apartment on Riverside Drive, on the Upper West
Side of Manhattan. He turned a spare bedroom into ▼
Joel Spira, inventor of the solid-state dimmer and founder
of Lutron Electronics