1. Vacuum Tubes
Ericka Chorniak

2. Types Uses What are they?
Devices that control current between electrodes in an evacuated container through thermionic emission (the Edison Effect) of electrons from a heated filament or cathode. 
Current Density
Temperature
Electric field
Work Function
Types
Diodes
Triodes
Tetrodes
Pentodes
Uses
Amplifiers
Rectifiers
Detectors
Source: Svjo from

3. 1904 – The first diode (Edison) 1919 – Tetrode tubes were invented
~1807 – Prototype for incandescent light bulb
1874 – Crystal use for detection discovered
1894 – Crystal radio detectors used
1906 – Prototype for Triode
1926 – Tetrodes became common, Pentode invented
1883 – Thermionic Emission established (Edison)
1904 – The first diode (Edison)
1919 – Tetrode tubes were invented
1873 – Thermionic Emission Reported (Guthrie)
1960s – Use of silicon transistors
Switch from crystal detectors to vacuum tube detectors in 1920s
Tetrodes were common by 1926
Source: reporterresume.net

4. Diodes Uses: Amplify Two Electrodes Sometimes called a Fleming Valve
To fix frustrating rectification process of crystal and cat’s whisker.
Uses:
As a rectifier
As a radio wave detector
Problem:
Amplify

5. Triodes A vacuum tube with three electrodes
Diode becomes a voltage controlled device
Lower the voltage of the grid relative to the cathode
This results in amplification of power and voltage
First electronic amplifiers and the start of 20th century electronics
Uses:
Telephones, radio transmitters and receivers
Problem:
Limited voltage gain
Problem = wasn’t very stable and had limited voltage gain
Source: Svjo from

6. Tetrodes Problem: A vacuum tube with four electrodes
The second grid is the screen grid
Lower positive voltage than anode
Voltage gain achieved
Voltage controlled devices
Solved instability and limited voltage gain problem of triodes
Used for voltage amplification due to the Miller effect
Beam Tubes are modified tetrodes (suppressor grid is replaced with beam-forming electrode)
Problem:
Secondary Emission
Voltage gain achieved because the voltage applied to the screen grid was bypassed to the ground through a capacitor allowing for the control grid and anode to be decoupled.
Miller effect basically says that one can achieve an increased voltage amplification if the input capacitance between the input and output terminals is increased.
The tetrode still had a problem: the emitted electrons had enough energy to cause electron emission of the anode. = electric field
Source: G4oep from

7. Source: Niteshade from audiocircile.com
Pentodes:
A vacuum tube with five active electrodes
The added grid is called the suppressor grid
Has same voltage as the cathode
Can be either wired to cathode or to an external pin
Radio Transmitters
Remote-Cutoff Tubes
Remote-cutoff tubes have nonuniform grid wire spacing to handle a wider range of input frequencies.
Source: Niteshade from audiocircile.com

8. Questions?

9. Backup slides

10. Cathode Types Pure Metals Monolayer Emitters Oxide Emitters
Tungsten and Tantalum
Relatively poor emitters  efficiency of emission is ~1 or 2 [mA/W]
Monolayer Emitters
Monoatomic layer of metal on another monoatomic layer of metal
For experiments that are less than 1900 K
Efficiency is ~ 5 [mA/W]
Oxide Emitters
Oxide coated cathodes (e.g. Barium Oxide coated Nickel cathodes)
Low voltage (less than 1000 V) applications
Efficiency is ~10 [mA/W]
Dispenser Cathodes
Cathodes that contain reservoir alkaline oxides used for replacement of decomposed cathode over time.
Emission increases as carbonate decomposes (as temperature increases)
Used for high current density applications
Efficiency is ~ 10 [mA/W]

11. Additional Sources
Reich, Herbert J. (13 April 2013). Principles of Electron Tubes (PDF). Literary Licensing, LLC. ISBN  Archived (PDF) from the original on 2 April 2017.
Fundamental Amplifier Techniques with Electron Tubes: Theory and Practice with Design Methods for Self Construction. Elektor Electronics. January 1, ISBN
"RCA Electron Tube 6BN6/6KS6". Retrieved
Hoddeson, L. "The Vacuum Tube". PBS. Archived from the original on 15 April Retrieved 6 May 2012.
Jones, Morgan (2012). Valve Amplifiers. Elsevier. p ISBN
Olsen, George Henry (2013). Electronics: A General Introduction for the Non-Specialist. Springer. p ISBN
Rogers, D. C. "Triode amplifiers in the frequency range 100 Mc/s to 420 Mc/s". Journal of the British Institution of Radio Engineers. 11 (12): 569–575. Archived from the original on 15 June , p.571 Archived 5 January 2018 at the Wayback Machine.
Bray, John (2002). Innovation and the Communications Revolution: From the Victorian Pioneers to Broadband Internet. IET. ISBN Archived from the original on 3 December
Guthrie, Frederick (1876). Magnetism and Electricity. London and Glasgow: William Collins, Sons, & Company. Archived from the original on 17 May 2015.
Thomas A. Edison U.S. Patent 307,031 "Electrical Indicator", Issue date: 1884
Guarnieri, M. (2012). "The age of vacuum tubes: Early devices and the rise of radio communications". IEEE Ind. Electron. M. 6 (1): 41–43. doi: /MIE
White, Thomas, United States Early Radio History, archived from the original on 18 August 2012
"Mazda Valves". Archived from the original on Retrieved
"Robert von Lieben — Patent Nr Dated November 19, 1906" (PDF). Kaiserliches Patentamt. 19 November Archived (PDF) from the original on 28 May Retrieved 30 March
"Archived copy". Archived from the original on 5 October Retrieved 21 August 2013.
Räisänen, Antti V.; Lehto, Arto (2003). Radio Engineering for Wireless Communication and Sensor Applications. Artech House. p. 7. ISBN
J.Jenkins and W.H.Jarvis, "Basic Principles of Electronics, Volume 1 Thermionics", Pergamon Press (1966), Ch.1.10 p.9

12. Additional Sources Continued
Guarnieri, M. (2012). "The age of vacuum tubes: the conquest of analog communications". IEEE Ind. Electron. M. 6 (2): 52–54. doi: /MIE
Introduction to Thermionic Valves (Vacuum Tubes) Archived 28 May 2007 at the Wayback Machine., Colin J. Seymour
"Philips Historical Products: Philips Vacuum Tubes". Archived from the original on 6 November Retrieved 3 November 2013.
Baker, Bonnie (2008). Analog circuits. Newnes. p ISBN
Modjeski, Roger A. "Mu, Gm and Rp and how Tubes are matched". Välljud AB. Archived from the original on 21 March Retrieved 22 April 2011.
Ballou, Glen (1987). Handbook for Sound Engineers: The New Audio Cyclopedia (1st ed.). Howard W. Sams Co. p ISBN Amplification factor or voltage gain is the amount the signal at the control grid is increased in amplitude after passing through the tube, which is also referred to as the Greek letter μ (mu) or voltage gain (Vg) of the tube.