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| A bright idea that changed the modern era |
One fine day a scientist named Thomas Edison
found that a small current passed from heated lamp filament to a metal plate mounted inside the vacuum envelop.Today this is known as the "Edison Effect"(figure (a)).The interesting thing is that the battery is only necessary to heat the filament.Electrons would still flow if a nonelectrical heat source was used.
Then in 1904 an adviser from Marconi Wireless Company named John Flemming found that an externally applied current only passed in one direction from filament to plate(figure (b)) but not the reverse direction. This invention was Vacuum diode.
In those days these vacuum diodes are used to convert alternating
currents to DC.
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| VACUUM DIODE |
The addition of third electrode by Lee DeForest as shown in figure
below(figure (c))
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This invention is know as an Audion Tube.That's
it the era of electronics began with this invention.
In 1948 a small device named Transistor was invented and this device achieved approximately the same effect as the Audion tube but vastly smaller space and with less material.
Q) What is solid-state electronics?
A)Transistors control the flow of electrons through solid semiconductor substance rather than through a vacuum, so transistor technology is often referred to as solid-state technology.
