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Development Of Edison's Effect 

Picture of Twisting Animated Screw Bulb

   
    

 

 

 

  
   

Marconi Radio Company!

Thomas Edison in 1883 noticed that electrical current flowing through a light bulb's filament could make the wire so hot that electrons boiled off, sailing through the vacuum inside the light bulb to a metal plate that had positive charge. Because Edison didn't see any way the phenomenon would help him perfect the light bulb, all he did was to make a notation of the effect, which he named as the Edison Effect. The Edison effect remained on the shelf until 1904, when a former employee; inventor John Flemming went to work for Marconi Radio Company! John Flemming first assignment was to find a better way to receive radio signals. Flemming began experimenting with the Edison effect. He discovered that radio waves passing through an airless tube created a varying direct current, which could be used with headphones to reproduced the sound carried by the waves.

 

 

 

Flemming named his discovery, the oscillation valve and proceeded to make an application for patent of his oscillation valve. Thomas Edison was first to discovered the Edison effect but he had no idea of how to implement his discovery. Both Flemming and Marconi employed the Edison effect technology.

Lee De Forest's Vacuum Tube

Marconi chose another less expensive technology, using a crystal wave detector. However, both Flemming and Marconi discoveries sat on the shelf. It wasn't until radio pioneer Lee De Forest read about Flemming's valve and built one himself.  The valve Lee De Forest created in 1906 had something new; a grid made of nickel wire which he placed between the filament and the plate. Applying even a small amount of electrical charge to the grid disrupted the flow of electrons from the filament to the plate! This signalled the beginning of the vacuum tube which eventually let a small amount of electrical current control a much larger flow of current.

Transistorized Amplifiers

If you are not old enough to be part of the baby boom generation, you may never have seen more than one type of vacuum tube; the cathode ray tube that displays images on desktop PC monitors and the ordinary TV screen. Except for CRTs and in sound systems of the audiophiles who swear vacuum tube

amplifiers are far more superior to transistorial amps. Vacuum tubes are rarely used in modern electronics. It isn't the amplifying abilities of the vacuum tubes that have made it one of the seminal discoveries of science! It is the vacuum tube's ability to act as a switch! When a small amount of current was applied to the grid, it turned off a much stronger current. In other words it turn off the electricity going to the grid, and the larger current is switched back on! On, off. off, on! Actually, it is quite simple when you think about it! The two-pronged concept of on and off also maps perfect with the binary system, which uses only 0 and 1 to represent all numbers making it possible to manipulate a roomful of vacuum tubes!

   
  

 

 
 

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