Saturday, February 13, 2016


JFK+50:  Volume 6, No. 1858


Menlo Park, New Jersey (JFK+50) One hundred thirty-six years ago today, February 13, 1880, Thomas Alva Edison* observed, for the first time, a phenomenon which would lead to his development of the first practical incandescent lamp.  

This phenomenon, later known as the Edison Effect, had first been reported by British scientist Frederick Guthrie in 1873.  Guthrie found that a red hot iron sphere with a negative charge would lose its charge, but would not with a positive charge.

The Edison Effect is described as "the classic example of...thermionic emission...or the emission of electrons from a hot cathode into a vacuum." This effect is important in the operation of many electronic devices. Today, this one-way flow from the hot element to a cool plate is accomplished by the diode.

Mr. Edison was in the process of attempting to find out why lamp filaments broke and uneven blackening occurred in his incandescent bulbs.  Finding that the current from the hot filament increased rapidly with increased voltage, he applied for a patent for a voltage regulator, the first U.S. patent of its type.

In 1904, the Edison Effect was put to use in converting a weak alternating current into a direct current to activate a meter or telegraph by British physicist John Fleming.  His work led to the invention of the first vacuum tube which later would be replaced by the transistor.

While Thomas Edison is credited with the invention of the electric light, light bulbs had been around for a number of years.  Those early electric bulbs, however, were expensive, unreliable and short-lived. 

"By creating a vacuum inside the bulb, finding the right filament to use and running lower voltage in the bulb," Edison was able to create an electric bulb which was long-lasting, reliable and affordable.  Mr. Edison was granted U.S. Patent #223,898 for the Electric Lamp on January 27, 1880.

By the time he was through, Thomas Alva Edison had been granted 1093 patents by the United States Patent Office and earned the nickname "Wizard of Menlo Park."  Mr. Edison has been described as "the most prolific and influential inventor of all time."

*Thomas Alva Edison (1947-1931) was born in Milan, Ohio but grew up in Port Huron, Michigan.  He had only 3 months of formal education but was home-schooled by his mother.  TAE became a telegraph operator for Western Union before beginning his career as an inventor in Newark, NJ.

His "invention factory" at Menlo Park was the first industrial research laboratory in the world.  It was there that he invented the electric lamp and phonograph.


"The Edison Effect and its modern applications," by Clayton H. Sharp, Journal of the American Institute of Electrical Engineering, Vol. 41, No. 1, January 1922.

"Thomas Edison and the Electric Lamp, Patented Jan 27, 1880," by Gene Quinn, January 26, 2014,

"Thomas Edison's Laboratory,"

A Replica of
Thomas Edison's
Carbon Filament Lamp
Photo by John White (2016)