The Edison effect is the name given to a phenomenon in which electrons flow from a heated element, such as a light bulb filament, through a vacuum to a positively charged metal plate. In this paper, a low-cost approach using automobile taillights is used to demonstrate this phenomenon.
In early 1880, while attempting to find a light bulb filament with long life, Thomas Edison found that a carbon filament worked well. However, even this solution was deemed unsatisfactory, for after a few hours of operation carbon from the filament was observed on the inside walls of the bulb. Edison’s assistant noticed that the carbon seemed to be coming from the filament and appeared to be moving through the vacuum onto the wall of the bulb. Edison determined electric charge was flowing not only through the filament but also through the evacuated bulb. In order to measure this flow, he made...
