Purpose: to provide an electric
light-source, to replace gas light or
The electric light bulb was an almost unbelievable
produced almost the same idea, independently, at
about the same time.
Joseph Swan was first, by a whisker, but didn't patent his
Edison started making bulbs, and accused Swan of copying.
for Swan, there was a small difference between the processes.
problem was solved by Edison and Swan forming a joint company
to produce bulbs.
The modern light bulb consists of a filament (coiled tungsten
wire) through which electricity flows. The
filament becomes extremely hot and glows brightly inside the
glass bulb. Early bulbs used bamboo, and
even coated cotton thread, as a filament. Tungsten is better.