It is necessary to maintain vacuum in a vacuum tube to provide the electrons a free path from cathode to anode without triggering ionization. If there was air or some other gas in the tube, the electron flow would cause it to ionize and the control grid would have reduced or even no control of the conduction of the tube.
There are gas filled tubes that depend on this ionization: for example in thyratrons, once the control grid starts conduction ionization takes over and the grid has no more control, you have to turn off the B+ supply in some way to reset it.
A vacuum tube is simply a tube with no oxygen nor carbon dioxide in it (aka no air).
Kilobytes and vacuum tubes are not in the same category. At best, a twin triode vacuum tube is a single flip-flop and can hold 1 bit of information, making a vacuum tube about 0.000122 of a kilobyte.
an electron tube containing a near-vacuum that allows the free passage of electric current.
The following stores sell a vacuum tube. Walmart, Home Hardware, Rona, Totems, and much more. Some of the stores listed might not sell a vacuum tube depending where they are located. These stores are located in Canada.
There were obvious differences between the trasisitor and the vacum tube. The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube. One transmisor was the equivalent 40 vacuum tubes. They also didn't produce heat compare it to a vacuum tubes. Conduct electricity faster and better than vacuum tubes.
the vacuum tube
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A vacuum tube does not contain any gases. All the gases are evacuated from the tube and only vacuum is left.
A vacuum tube is simply a tube with no oxygen nor carbon dioxide in it (aka no air).
Millman's theorem
who made the vacuum tubes
The transistor replaced the vacuum tube, allowing radios to get much smaller and portable.
Kilobytes and vacuum tubes are not in the same category. At best, a twin triode vacuum tube is a single flip-flop and can hold 1 bit of information, making a vacuum tube about 0.000122 of a kilobyte.
an electron tube containing a near-vacuum that allows the free passage of electric current.
why we are maintain vacuum in steam turbine at steam outlet or exhaust side
cellphone
A vacuum tube can be tested with an array of power supplies and meters if you have detailed schematics and tube test procedures. However it is easiest to use a standard Tube Tester. In the day there you could find self service box-like testers in certain drug stores or part supply stores. Most metropolitan areas still have electronic stores that specialize in selling Radio and Vacuum Tubes, and they would have tube testers that you can access. Ebay lists a number of vacuum tube testers but you need to make sure its working and that it has the booklet to set the many test switch positions for the particular tube you want to test.