Joel Spira (businessman)

Joel Solon Spira (March 1, 1927 – April 8, 2015) was an American inventor, entrepreneur, and business magnate.

He invented a version of the light-dimmer switch for use in homes around the United States and led his Lutron Electronics Company into the production of lighting controllers.

Early life

Spira was born in New York City in 1927. He received a Bachelor of Science degree in physics from Purdue University in West Lafayette, Indiana, in 1948 and became a benefactor with his wife, including the School of Mechanical Engineering Ruth and Joel Spira Award and others.

In the 1950s, he worked for an aerospace company, where he was assigned to develop a reliable trigger for atomic weapons. Suggested by others at the laboratory, he called on the thyristor, a solid state semiconductor. During his research, he recognized that the device could also be employed to vary the intensity of light.

A lighting dimmer existed at the time, but was expensive, complicated, and necessitated the use of large rheostats, about 10 in (25 cm) in size. Though there were dimming devices already in use for theater lighting, they were far too big and bulky for use in homes. Spira successfully manipulated a thyristor, a solid-state semiconductor small enough to fit into the wall box that housed a standard light switch. Unlike theatrical dimmers, Spira's standalone device was small enough for home application.