Post on 16-Dec-2015
HISTORY & BACKGROUND
Who first discovered the idea of Vacuum tubes?
Where was the first Vacuum tube invented?
Who was It invented by?
What was is it first used for?
TYPES OF VACUUM TUBES
Electrodes( Electron Emitters)
2 electrodes + 1 cathode + 1 anode = 1 Diode (1904)
3 electrodes + 1 cathode + 1 anode = 1 Triode (1906)
4 electrodes + 1 cathode + 1 anode = 1 Tetrode(1926)
5 electrodes + 1 cathode + 1 anode = 1 Pentode(1928)
Edison: “Edison Effect”
Fleming: Invented and patented the first tube
De Forest: Starts the Electronic revolution with the invention of the Audion Tube
KEY PLAYERS
Coolidge: Invented x-ray tubes
Schottky: Invented the tetrode (multiple grid vacuum tube)
Langmuir: Observed emission and their behavior In vacuum tubes which lead to a creation of a variety of tube types
KEY PLAYERS
MORE ON V
ACUUM TUBES
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HOW IT WORKS
Converts heat to electricity
Vacuum tubes can take weak signals and make then stronger (amplify)
Tubes can also start and stop the flow of electricity instantly (switch)
Glow when its turned on (heat from the cathode)
Anode +
no air (vacuum) Transfer of energy
Filament helps the
amplification of energy.
Cathode -
Have been around for ~10 years
“One way mirror” sun’s radiation is absorbed but can’t escape
(93% absorbed & 7% lost to reflection)
Vacuum wall prevents any losses by conduction /convection
Work better in lower temp unlike flat solar panels
More expensive than flat panel but cost has been driven down due to demand
WHERE THEY’RE USED: VACUUM TUBE SOLAR PANELS
Also known as valve amp, were the first type of guitar amplifiers
Heat is converted to electricity which is then added to boost the weak guitar signal.
Can switch from clean to distorted sound easily
Warmer tone / full tone
Still around because of sound quality!
WHERE THEY’RE USED: GUITAR AMPLIFIERS
Vacuum Tube vs Transistors
Both can switch electricity on and off
Tubes, similar to light bulbs, generate a lot of heat and burn out
Transistors are much smaller and have longer life spans
Assisted in the construction of more advanced circuits
Important to the development of modern machine
WHERE THEY’RE USED: COMPUTERS
VACUUM TUBES
A D V A N T A G E S
Can be replaced easily if they fail
Can be used in a wide range of applications (radios, amplifiers, strobe lights, juke boxes…)
Provide better sound quality in professional sound equipment
D I S A D V A N T A G E S
Heavy
Generate a lot of unwanted heat
Require at least 11 sec to warm us compared to transistors which are instant
Require a lot of power