Introduction to Electron Tubes
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Fundamentals of Microelectronics Chapter 3 Diode Circuits
9/17/2010 Fundamentals of Microelectronics CH1 Why Microelectronics? CH2 Basic Physics of Semiconductors CH3 Diode Circuits CH4 Physics of Bipolar Transistors CH5 Bipolar Amplifiers CH6 Physics of MOS Transistors CH7 CMOS Amplifiers CH8 Operational Amplifier As A Black Box 1 Chapter 3 Diode Circuits 3.1 Ideal Diode 3.2 PN Junction as a Diode 3.3 Applications of Diodes 2 1 9/17/2010 Diode Circuits After we have studied in detail the physics of a diode, it is time to study its behavior as a circuit element and its many applications. CH3 Diode Circuits 3 Diode’s Application: Cell Phone Charger An important application of diode is chargers. Diode acts as the black box (after transformer) that passes only the positive half of the stepped-down sinusoid. CH3 Diode Circuits 4 2 9/17/2010 Diode’s Action in The Black Box (Ideal Diode) The diode behaves as a short circuit during the positive half cycle (voltage across it tends to exceed zero), and an open circuit during the negative half cycle (voltage across it is less than zero). CH3 Diode Circuits 5 Ideal Diode In an ideal diode, if the voltage across it tends to exceed zero, current flows. It is analogous to a water pipe that allows water to flow in only one direction. CH3 Diode Circuits 6 3 9/17/2010 Diodes in Series Diodes cannot be connected in series randomly. For the circuits above, only a) can conduct current from A to C. CH3 Diode Circuits 7 IV Characteristics of an Ideal Diode V V R = 0⇒ I = = ∞ R = ∞⇒ I = = 0 R R If the voltage across anode and cathode is greater than zero, the resistance of an ideal diode is zero and current becomes infinite. -
El156 Audio Power
EL156 AUDIO POWER Gerhard Haas Thanks to its robustness, the legendary EL156 audio power pentode has found its way into many professional amplifier units. Its attraction derives not just from its appealing shape, but also from its impressive audio characteristics. We therefore bring you this classical circuit, updated using high- quality modern components. 28 elektor electronics - 3/2005 AMPLIFIER Return of a legend The EL156 was manufactured in the enough to give adequate sensitivity, electrolytic capacitor: this voltage is legendary Telefunken valve factory in even before allowing any margin for further filtered on the amplifier board. Ulm, near the river Danube in Ger- negative feedback. The ECC81 many. The EL156 made amplifiers with (12AT7), however, which has an open- It is not possible to build an ultra-lin- an output power of up to 130 W possi- loop gain of 60 and which can be oper- ear amplifier using the EL156 with a ble, using just two valves in the output ated with anode currents of up to high anode voltage. The same goes for stage and one driver valve. Genuine 10 mA, can be used to build a suitably the EL34. The output transformer is EL156s are no longer available new at low-impedance circuit. therefore connected in such a way that realistic prices, and hardly any are Two EL156s can be used to produce an the impedance of the grid connection available second-hand. The original output power of 130 W with only 6 % to the output valve is much lower than devices used a metal valve base which distortion. -
Valve Biasing
VALVE AMP BIASING Biased information How have valve amps survived over 30 years of change? Derek Rocco explains why they are still a vital ingredient in music making, and talks you through the mysteries of biasing N THE LAST DECADE WE HAVE a signal to the grid it causes a water as an electrical current, you alter the negative grid voltage by seen huge advances in current to flow from the cathode to will never be confused again. When replacing the resistor I technology which have the plate. The grid is also known as your tap is turned off you get no to gain the current draw required. profoundly changed the way we the control grid, as by varying the water flowing through. With your Cathode bias amplifiers have work. Despite the rise in voltage on the grid you can control amp if you have too much negative become very sought after. They solid-state and digital modelling how much current is passed from voltage on the grid you will stop have a sweet organic sound that technology, virtually every high- the cathode to the plate. This is the electrical current from flowing. has a rich harmonic sustain and profile guitarist and even recording known as the grid bias of your amp This is known as they produce a powerful studios still rely on good ol’ – the correct bias level is vital to the ’over-biased’ soundstage. Examples of these fashioned valves. operation and tone of the amplifier. and the amp are most of the original 1950’s By varying the negative grid will produce Fender tweed amps such as the What is a valve? bias the technician can correctly an unbearable Deluxe and, of course, the Hopefully, a brief explanation will set up your amp for maximum distortion at all legendary Vox AC30. -
Vacuum Tube Theory, a Basics Tutorial – Page 1
Vacuum Tube Theory, a Basics Tutorial – Page 1 Vacuum Tubes or Thermionic Valves come in many forms including the Diode, Triode, Tetrode, Pentode, Heptode and many more. These tubes have been manufactured by the millions in years gone by and even today the basic technology finds applications in today's electronics scene. It was the vacuum tube that first opened the way to what we know as electronics today, enabling first rectifiers and then active devices to be made and used. Although Vacuum Tube technology may appear to be dated in the highly semiconductor orientated electronics industry, many Vacuum Tubes are still used today in applications ranging from vintage wireless sets to high power radio transmitters. Until recently the most widely used thermionic device was the Cathode Ray Tube that was still manufactured by the million for use in television sets, computer monitors, oscilloscopes and a variety of other electronic equipment. Concept of thermionic emission Thermionic basics The simplest form of vacuum tube is the Diode. It is ideal to use this as the first building block for explanations of the technology. It consists of two electrodes - a Cathode and an Anode held within an evacuated glass bulb, connections being made to them through the glass envelope. If a Cathode is heated, it is found that electrons from the Cathode become increasingly active and as the temperature increases they can actually leave the Cathode and enter the surrounding space. When an electron leaves the Cathode it leaves behind a positive charge, equal but opposite to that of the electron. In fact there are many millions of electrons leaving the Cathode. -
The Development of the Vacuum Tube Creators
The Knowledge Bank at The Ohio State University Ohio State Engineer Title: The Development of the Vacuum Tube Creators: Jeffrey, Richard B. Issue Date: May-1928 Publisher: Ohio State University, College of Engineering Citation: Ohio State Engineer, vol. 11, no. 7 (May, 1928), 9-10. URI: http://hdl.handle.net/1811/34260 Appears in Collections: Ohio State Engineer: Volume 11, no. 7 (May, 1928) THE OHIO STATE ENGINEER The Development of the Vacuum Tube By RICHARD B. JEFFREY, '31 The history of the vacuum tube began with the discovery of the Edison Effect. This, like a great many other important discoveries, was an acci- dent. Edison, while experimenting with his in- candescent lamps, had placed more than one fila- output ment in the same bulb, and he noticed that if one of the filaments was held positive with respect to the other a current would flow through the bulb. He also found that this positive element, or, as it is now called, plate, did not have to be hot to sustain this current flow. This phenomenon li—- H was known for some time as a curiosity, but noth- 1 +90 to \35 ing more. Then Fleming, an English experiment- +4-5 er, noticed that if an alternating current were The screen-qrid tube (tetrode). applied to this plate the current would flow only plicated system by making use of the rectifying when the plate was positive. In other words, the properties of a crystal, notably galena. When tube acted as a rectifier, allowing the current to signals were received in this way it was the signal flow in only one direction. -
The EL34 Power Tube HI-'I
The EL34 Power Tube HI-'I .... o.l"r A lp Musical Evaluations of a Classic Design .... A_I . 4.551 Single. Ended EL·84 Stereo Amp ~ _ .... ,���\� . -""" ".. - ...-., p.,.��",-, �. 1""""' -�,�.. � . oPf' ' ".".. ._ '" "'� .,_ "'�•• '" "'� ...- ' ,t\1".' ,w ' � "'\)U'�..,. ,\ 1\ ' ��-;---""\.\. ",.-" " ".,... "", ""�_ " tt"�" ,....-" ...........,...1"'" '�" ""t\1 _,.,.""" ....'" 'r·\ �'� . � ......,. �,,,. � ,..' ",...., \PJOl8'i .... �,�oPf',.,....;:.. O\ �,cl\ ., .... " , � ...,,.. AA �r- . · :::- ,,<,<, ,. ..""'"':k ...0'\1. � ':;: "",;: .. .._ " r ,...,.. _ "" " .-;.,,...""".... ",.... ......,.,.,,, -;;. ,... :;..,� _ """;.... -� . 0 """ " . ,,..,. ,t" ,,'" <""" , .-_,.;.;.''' � .. '''''''-o<f' _ ....;;; .,;::; , -- '" " ,.,...,.. "" .'" ::, ,t"� ��. ...,.,..,.;.;."1"" ''/'''' � _.� "" f"'� . � ' M'''" ' "- """",,; ,.of .,.,..� .. ...,. ' "' 1" '". '_1"""' . .. " ,,,,,,,,,,,,,,,_ f"""";""';..::: .,... " '�,;;.;:' ' ......,,..,..,. _-:: -__':1oPf' ::;;'", --''''"", ""","" ", ' �':::', � ' ""r; """"-"' .''''''''�}.. ,t\1 \ �·, � ot ,;: "" � ,.,. ---� , _.at" � t\JV" �� � 'i"'f'- " .::... .. .... �. , ,�,....,.' .....;. _ ...-:> ".... JC8'I\\ -, \�..- WOl\ """,.""''1"'"- �""'" � '-,�� 6<1\"""- ' ""'..,... � ...... � 6U'." �. - ,t\1 , . _ , "'" 1J>b\"� ��, oPf''' .,..-._ " "" .0. " ..... ���_���\t"�'".. ' ....... "" "",",. N ��:L [\l\'J � ��i y< • D T 0 • , 5 P A G • A N D N D u 5 T • y N • w 5 Beware of FakeNOS Tubes! CE Distribution US Distributor for Electronic Tubes VTV Issue # 1 6 JJ Over the last year or so, we have JJ Electronic, -
Operation, Tetrode, Pentode in the Single-Ended, Class-A
10-76 10. Guitar Amplifiers 10.5.1 Single-ended (class A)-operation, tetrode, pentode In the single-ended, class-A power-stage, one (single) power-tube operates in common- cathode configuration with the output transformer being part of the plate circuit (transformer- coupling). Without AC-drive (“quiescent state”), a stable balance appears – it is called the operating point (OPP). The characteristics shown in Fig. 10.5.2 yield an OPP at 250 V and 48 mA, if a voltage of -7.5 V between (control) grid (g1) and cathode is chosen. This can be done e.g. by using a cathode-resistor of 142 Ω. The cathode-current (the sum of the 48-mA- plate-current and the 5-mA-screen-grid-current) will then generate a positive cathode-voltage of + 7.5 V (relative to ground). With the control-grid at ground-potential (Ug1 = 0) a control- grid-to-cathode-voltage of -7.5 V results (i.e. the control grid is negative vs. the cathode). Fig. 10.5.2: Output characteristics of the EL84, power-stage circuit (single-ended class-A operation). AP = OPP As a drive signal appears (Ug1 ≠ 0), plate-voltage and –current change. As a first approach, it will be sufficient to consider the transformer in the plate-circuit as a large inductance connected in parallel with an ohmic resistor (Chapter 10.6). In this model we have only pure DC flowing through the inductance, and only pure AC flowing through the resistor. With a drive-signal present, the Ua/Ia-point will move along the load-line given in Fig. -
1999-2017 INDEX This Index Covers Tube Collector Through August 2017, the TCA "Data Cache" DVD- ROM Set, and the TCA Special Publications: No
1999-2017 INDEX This index covers Tube Collector through August 2017, the TCA "Data Cache" DVD- ROM set, and the TCA Special Publications: No. 1 Manhattan College Vacuum Tube Museum - List of Displays .........................1999 No. 2 Triodes in Radar: The Early VHF Era ...............................................................2000 No. 3 Auction Results ....................................................................................................2001 No. 4 A Tribute to George Clark, with audio CD ........................................................2002 No. 5 J. B. Johnson and the 224A CRT.........................................................................2003 No. 6 McCandless and the Audion, with audio CD......................................................2003 No. 7 AWA Tube Collector Group Fact Sheet, Vols. 1-6 ...........................................2004 No. 8 Vacuum Tubes in Telephone Work.....................................................................2004 No. 9 Origins of the Vacuum Tube, with audio CD.....................................................2005 No. 10 Early Tube Development at GE...........................................................................2005 No. 11 Thermionic Miscellany.........................................................................................2006 No. 12 RCA Master Tube Sales Plan, 1950....................................................................2006 No. 13 GE Tungar Bulb Data Manual................................................................. -
ECE 340 Lecture 22 : Space Charge at a Junction
ECE 340 Lecture 22 : Space Charge at a Junction Class Outline: •Space Charge Region Things you should know when you leave… Key Questions • What is the space charge region? • What are the important quantities? • How are the important quantities related to one another? • How would bias change my analysis? M.J. Gilbert ECE 340 – Lecture 22 10/12/11 Space Charge Region To gain a qualitative understanding of the solution for the electrostatic variables we need Poisson’s equation: Most times a simple closed form solution will not be possible, so we need an approximation from which we can derive other relations. Consider the following… Doping profile is known •To obtain the electric field and potential we need to integrate. •However, we don’t know the electron and hole concentrations as a function of x. •Electron and hole concentrations are a function of the potential which we do not know until we solve Poisson’s equation. Use the depletion approximation… M.J. Gilbert ECE 340 – Lecture 22 10/12/11 Space Charge Region What does the depletion approximation tell us… 1. The carrier concentrations are assumed to be negligible compared to the net doping concentrations in the junction region. 2. The charge density outside the depletion region is taken to be identically zero. Poisson equation becomes… Must xp = xn? M.J. Gilbert ECE 340 – Lecture 22 10/12/11 Space Charge Region We are already well aware of the formation of the space charge region… The space charge region is characterized by: Na < Nd •Electrons and holes moving across the junction. -
Philips DEALING with TECHNICAL PROBLEMS
VOL. 5 N~. 3 . Philips DEALING WITH TECHNICAL PROBLEMS. RELATING TO THE PRODUCTS, PROCESSES AND. INVESTIGATIONS OF N.V. PHILIPS' GLOEILAMPENFABRIEKEN EDITED BY THE RESEARCH LABORATORY OF N.V. PHILIPS' GLOEILAMPENFABRIEKEN, EINDHOVEN, HOLLAND TESTING A~PLIFIER OUTPUT VALVES BY MEANS OF THE 'CAT~ODE RAY TUBE hy A. J. HEINS van der VEN. 621.317.755: 621.396.645 I n testing amplifier output valves, the most important data are contained in the In' v.. diagram if one knows over which part of the diagram the values of voltage and current prevailing during operatien range, i;e. if the position of the load line is known. The la- Vn 'diagrams as well as the load lines can very easily b~ obtained with the help of a 'cathode ray tube. The necessary apparatus is described in this article. A number of auxiliary ar- rangernents are also studied, by which the axes and the necessary calibration lines in the diagram can be traced on the fluorescent screen, and which make it possible to. cause the diagrams of two .output valves which are to be compared to appear simultancously on the screen. In order to obtain the load line in the correct place in the diagram, use must he made of dir'ect current push-pull amplifiers for the deflection voltages of the cathode ray tube. The position of the load line upon inductive loading is discussed and explained by a number of examples. In conclusion one,npplication of the instaflation in the develop- ment of output pentodes is dealt with. If one wishes to characterize briefly the perfor- quantrties are to some degree dependent _on the mance of an output valve of !tn amplifier or radio loading impedance which is included in the anode set, it is enough to give the sensitivity, the distor- circuit, it is first necessary to find out how the loa'd- tion as a function of the power output, and in some ing of the ~alve is e~pl'esse~ in the Ia- V~ curve.' , cases the maximum power which can he delivered mA without grid current flowing. -
Varian Mw 3 % H
ORNL/Sub-75/49438/2 BP n ^TfFl varian mw 3 % h NOTICE PORTIONS OF TV'!? HFTL0'' SHE M.I.HGIB'.E. IF lT~~rvnrT;irri*"rr?.--p. tf.3 iwaito'jia 1 co1;;/ -o psrrnii the broadest possible avail- ability. FINAL REPORT MILLIMETER WAVE STUDY PROGRAM u by H.R. JORY, E.L. LIEN and R.S. SYMONS ft, 0 {I Order No. Y-12 11Y-49438V j November 1975 report prepared by Varian Associates Palo Alto Microwave Tube Division 611 Hansen Way o Palo Alto, California 94303 under subcontract number 11Y-49438V ; for ' ' r>4 OAK RIDGE NATIONAL LABORATORY * ° Oak Ridge, Tennessee 37830 operated by UNION CARBIDE CORPORATION for the nrsTKIUUTiON 01? 'ijl;.;?!---''--^-'.^-^''' UNLLMIT DEPARTMENTS ENERGY FINAL REPORT MILLIMETER WAVE STUDY PROGRAM by H. R. Jory, E. L Lien and R, S. Symons - NOTICE- Urn report Mas piepated as an account, of worl; sponsored by die Untied Stales Government. Neither Die United State* not the United States Pepastment of l.nergy, tiar any of1 their employees, nnr any of then contractors. subcontractor or their employees, makes any warranty, express or implied, or assumes any legal liability oi responsibility for tlie accuracy, completeness of usefulness of any information, apparatus, product or process disclovd. or represents that its use would not mUmfe pnvately owned npjits. Order No, Y-12UY-49438V November 1975 « 0 " report prepared by Varian Associates Palo Alto Microwave Tube Division 611 Hansen Way Palo Alto, California 94303 K< under subcontract number 11Y-49438V for OAK RIDGE NATIONAL LABORATORY Oak.RitJge-J'ennessee 37830 c.-..operatedjby U N 10N CARBiDE^G0RP0RATI0N, o <J>c l . -
Bias Circuits for RF Devices
Bias Circuits for RF Devices Iulian Rosu, YO3DAC / VA3IUL, http://www.qsl.net/va3iul A lot of RF schematics mention: “bias circuit not shown”; when actually one of the most critical yet often overlooked aspects in any RF circuit design is the bias network. The bias network determines the amplifier performance over temperature as well as RF drive. The DC bias condition of the RF transistors is usually established independently of the RF design. Power efficiency, stability, noise, thermal runway, and ease to use are the main concerns when selecting a bias configuration. A transistor amplifier must possess a DC biasing circuit for a couple of reasons. • We would require two separate voltage supplies to furnish the desired class of bias for both the emitter-collector and the emitter-base voltages. • This is in fact still done in certain applications, but biasing was invented so that these separate voltages could be obtained from but a single supply. • Transistors are remarkably temperature sensitive, inviting a condition called thermal runaway. Thermal runaway will rapidly destroy a bipolar transistor, as collector current quickly and uncontrollably increases to damaging levels as the temperature rises, unless the amplifier is temperature stabilized to nullify this effect. Amplifier Bias Classes of Operation Special classes of amplifier bias levels are utilized to achieve different objectives, each with its own distinct advantages and disadvantages. The most prevalent classes of bias operation are Class A, AB, B, and C. All of these classes use circuit components to bias the transistor at a different DC operating current, or “ICQ”. When a BJT does not have an A.C.