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Joel Solon Spira Edit Profile

entrepreneur , inventor , business magnate

Joel Solon Spira, American electronics company executive. Member National Academy Engineering, William Oughtred Society.


Spira, Joel Solon was born on March 1, 1927 in New York City.


Bachelor of Science in Physics, Purdue University, 1948.


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. 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. He resigned from his job at the aerospace laboratory to concentrate on refining the device.

Spira thence went onto conduct experiments on a ping-pong table in his Riverside Drive apartment in New York City, which led to a device capable of dimming the lighting in a home or office setting. Spira became, as a result of his discovery, best known for his initial, seminal invention: the first successful solid state-electronic dimmer. He filed for a patent on July 15, 1959 (US 3,032,688).

The privately held firm, whose headquarters remains there today, has grown into an international manufacturer and distributor of not only dimmers, but also of motorized and automated window-covering systems, as well as lighting fixtures and temperature controls. Spira headed the firm for 54 years and more recently became chair of the board and research director. He died in 2015 at the age of 88 from a heart attack in Springfield Township, Pennsylvania.

Just prior to his death of natural causes and remaining active to some degree at Lutron, he was collaborating with company engineers on a new device.


  • 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.


Member National Academy Engineering, William Oughtred Society.


Married Ruth Rodale, November 7, 1954. Children: Susan, Lily, Juno.

Ruth Rodale

Susan Spira

Lily Spira

Juno Spira