MAGIC PRE Rev. A
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
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. -
INDUSTRIAL STRENGTH by MICHAEL RIORDAN
THE INDUSTRIAL STRENGTH by MICHAEL RIORDAN ORE THAN A DECADE before J. J. Thomson discovered the elec- tron, Thomas Edison stumbled across a curious effect, patented Mit, and quickly forgot about it. Testing various carbon filaments for electric light bulbs in 1883, he noticed a tiny current trickling in a single di- rection across a partially evacuated tube into which he had inserted a metal plate. Two decades later, British entrepreneur John Ambrose Fleming applied this effect to invent the “oscillation valve,” or vacuum diode—a two-termi- nal device that converts alternating current into direct. In the early 1900s such rectifiers served as critical elements in radio receivers, converting radio waves into the direct current signals needed to drive earphones. In 1906 the American inventor Lee de Forest happened to insert another elec- trode into one of these valves. To his delight, he discovered he could influ- ence the current flowing through this contraption by changing the voltage on this third electrode. The first vacuum-tube amplifier, it served initially as an improved rectifier. De Forest promptly dubbed his triode the audion and ap- plied for a patent. Much of the rest of his life would be spent in forming a se- ries of shaky companies to exploit this invention—and in an endless series of legal disputes over the rights to its use. These pioneers of electronics understood only vaguely—if at all—that individual subatomic particles were streaming through their devices. For them, electricity was still the fluid (or fluids) that the classical electrodynamicists of the nineteenth century thought to be related to stresses and disturbances in the luminiferous æther. -
Lee De Forest Claimet\He Got the Idea for His Triode ''Audion" From
Lee de Forest claimet\he got the idea for his triode h ''audion" from wntching a gas flame bum. John Ambrose Flen#ng thought that story ·~just so much hot air. lreJess telegraphy held excit m WIng promise at the beginning of the twentieth century. Peo ~With Imagination could seethe po.. tentlal thot 'the rematkoble new technology offered forworlct1Nk:le com munfcotion. However, no one could hove predicted the impact that the soon-to-be-developed "osdllotlon volve" ond "oudlon" Wireless-telegra phy detector& wauid have on elec tronics technology. Backpouncl. Shortly before 1900, · Guglielmo Morconl had formed his own company to develop wireless telegraphy technology. He demon strated that wireless set-ups on ships eot~ld~messageswlth nearby stations on other ships or on land. t The Marconi Company hOd also j transmitted messages across the EhQ Jish Channel. By the end of 1901. Mar coni extended the range of his equipmenttospantheAtlan1tcOcean. It was obvlgus. 1hot ~raph ~MeS with subrhatlrie cables and ihelr lnber ent flmltations woUld soon disappear, Ships· at sea would no longer be iso la1ed. No locatlon on Eorth would. be too remote to send and receive mes sages. Clear1y; the opportunity existed tor enormous tiOOnciql gain once Jelio ble equlprrient was avoltable. To that end, 1Uned electrical circuits were developed to reduce the band width of the signals produced by ,the spark transrnlf'tirs. The resonont clfcults were also used in a receiver to select one signal from omong several trans missions. Slm~deslgn principles for resonont ontennas were also being explored and applied, However, the senstflvlty and reUabltlty of the devices used to ctetectthe Wireless signals were still hln cterlng the development of commer () cial wireless-telegraph nefWorks. -
Anchorage Amateur Radio Club Next Meeting November 4Th
Volume 34 No. 11: November 2005 Anchorage Amateur Radio Club Next Meeting November 4th Program for November communications support for this race since its inception in Jim Wiley, KL7CC 1973. Lee Wareham, KL7DTH, will speak about his adventures Gordon Hartlieb AL1W has again volunteered for the Start flying from Alaska to Norway and back over the pole in his Communications Coordinator and need over 35 Hams for the Cessna 185 - this is the adventure where Ron Sheardown lost 4th of March 2006. his Soviet built AN2 biplane through the ice. I saw the presentation a few years ago, just after the event, and it was Jim Bruton KL7HJ has volunteered to replace Dan O’barr absolutely fascinating. KL7BD as The Re-start Coordinator as Dan’s new job does not allow for the time required for this job. He will need more Lee has some audio tapes excerpts of the conversations on the than 35 hams for the “real” start on the 5th of March 2006. ham radio (between himself and Jerry Curry, KL7EDK, in Fairbanks), which kept up continuously for the whole flight, Kristin Young, (a poor unguided non ham) is the HQ across and back. There will be time for questions. coordinator and is in need of 144 volunteers to fill HQ shifts of which 33 are Ham required. This is a 24/7 operation with +++++++++++++++++++++++++ 6hr. shifts from the 2nd of March thru the 21st of March 2006. Bernadette Anne, (another poor unguided non ham), is the Trail Communications Coordinator and has 48 positions to fill of which 24 are Hams, 6 more than last year. -
Photomultiplier Tubes 1)-5)
CHAPTER 2 BASIC PRINCIPLES OF PHOTOMULTIPLIER TUBES 1)-5) A photomultiplier tube is a vacuum tube consisting of an input window, a photocathode, focusing electrodes, an electron multiplier and an anode usu- ally sealed into an evacuated glass tube. Figure 2-1 shows the schematic construction of a photomultiplier tube. FOCUSING ELECTRODE SECONDARY ELECTRON LAST DYNODE STEM PIN VACUUM (~10P-4) DIRECTION e- OF LIGHT FACEPLATE STEM ELECTRON MULTIPLIER ANODE (DYNODES) PHOTOCATHODE THBV3_0201EA Figure 2-1: Construction of a photomultiplier tube Light which enters a photomultiplier tube is detected and produces an output signal through the following processes. (1) Light passes through the input window. (2) Light excites the electrons in the photocathode so that photoelec- trons are emitted into the vacuum (external photoelectric effect). (3) Photoelectrons are accelerated and focused by the focusing elec- trode onto the first dynode where they are multiplied by means of secondary electron emission. This secondary emission is repeated at each of the successive dynodes. (4) The multiplied secondary electrons emitted from the last dynode are finally collected by the anode. This chapter describes the principles of photoelectron emission, electron tra- jectory, and the design and function of electron multipliers. The electron multi- pliers used for photomultiplier tubes are classified into two types: normal dis- crete dynodes consisting of multiple stages and continuous dynodes such as mi- crochannel plates. Since both types of dynodes differ considerably in operating principle, photomultiplier tubes using microchannel plates (MCP-PMTs) are separately described in Chapter 10. Furthermore, electron multipliers for vari- ous particle beams and ion detectors are discussed in Chapter 12. -
A Practical Approach to Transist Vacuum Tube Amplifiers
A PRACTICAL APPROACH TO TRANSIST VACUUM TUBE AMPLIFIERS BY F. J. BECKETT TEKTRONIX, INC. ELECTRONIC INSTRUMENTATION GROUP DISPLAY DEVICES DEVELOPMENT Two articles published in past issues of Service Scope contained information that, in our experience, is of particular benefit in analyzing circuits. The first article was "Sim- plifying Transistor Linear-Amplifier Analysis" (issue #29, December, 1964). It describes a method for doing an adequate circuit analysis for trouble-shooting or evaluation pur- poses on transistor circuits. It employs "Transresistance" concept rather than the compli- cated characteristic-family parameters. The second article was "Understanding and Using Th6venin's Theorem" (issue #40, October, 1966). It offers a step-by-step explanation on how to apply the principles of ThBvenin's Theorem to analyze and understand how a circuit operates. Now we present three articles that will offer a practical approach to transistor and vacuum-tube amplifiers based on a simple DC analysis. These articles will, by virtue of additional information and tying together of some loose ends, combine and bring into better focus the concepts of "Transresistance." Part I THE TRANSISTOR AMPLIFIER INTRODUCTION Tubes and transistors are often used to- there is an analogy between the two. It 50, it seems pointless not to pursue this ap- gether to achieve a particular result. Vacu- is true of course, that the two are entire- proach to its logical conclusion. um tubes still serve an important role in ly different in concept; but, so often we In this first article we will look at a electronics and will do so for many years come across a situation where one can be transistor amplifier as a simple DC model ; to come despite a determined move towards explained in terms of the other that it is and then, in the second article, look at a solid state circuits. -
Lorentz Force Demonstrator
LORENTZ FORCE DEMONSTRATOR LFD001 1 10 2 9 3 4 8 5 6 7 Figure 1 GENERAL DESCRIPTION The LFD001 Lorentz Force Demonstrator is a “fine beam tube” device in which a sharply focused electron beam is projected into a vacuum containing a trace of inert gas. Ionization of the gas around the electron beam creates a glowing discharge marking the path of the electrons and helping to maintain the sharp focus of the beam. The demonstrator shows deflection of the beam by transverse electric fields and by magnetic fields of various orientations. The value of e/m can be found by bending the electron beam into a circular path with a homogeneous magnetic field and measuring the accelerating voltage of the electron gun, the strength of the magnetic field, and the radius of the circular beam path. The components of the device are shown in Figure 1: 1. “Fine beam” vacuum tube 6. Accelerating and deflection voltage controls 2. Helmholtz coils 7. Power and coil current controls 3. Transparent metric ruler 8. Accelerating voltage and coil current meters 4. Angle scale and pointer for tube 9. Mirror for parallax elimination 5. Current direction indicators 10. Case with black interior for better visibility 847-336-7556 1 www.unitedsci.com SPECIFICATIONS Fine beam vacuum tube Diameter: 160mm Rotation: tube and socket rotate ±180° Angle scale: 0° — ±180° x 5° Accelerating voltage: 250V max. Helmholtz coils: Coil mean diameter: 280mm Coil separation: 140mm 140 turns per coil Max. current: 2.5A Power supply unit: Accelerating voltage: 0—250V dc Coil current:0.5—2.5A, reversible, with current direction indicators Electrostatic deflecting voltage: 50—250V, reversible Accuracy of meters: ±2.5% Power input: 110VAC 60Hz, 45W Maximum continuous operation: 1 hour Operating conditions: Temperature: 0 – 40°C, Humidity: 20 –80% Dimensions: 35cm x 30cm x 45cm (l x w x h) Weight: 11kg CONTROLS 12 11 9 10 4 6 5 1 2 3 8 7 Figure 2 Figure 2 shows the front panel of the power supply unit: 1. -
Cathode Ray Tube
Cathode ray tube Quick reference guide Introduction The Cathode Ray Tube or Braun’s Tube was invented by the German physicist Karl Ferdinand Braun in 1897 and is today used in computer monitors, TV sets and oscilloscope tubes. The path of the electrons in the tube filled with a low pressure rare gas can be observed in a darkened room as a trace of light. Electron beam deflection can be effected by means of either an electrical or a magnetic field. Functional principle • The source of the electron beam is the electron gun, which produces a stream of electrons through thermionic emission at the heated cathode and focuses it into a thin beam by the control grid (or “Wehnelt cylinder”). • A strong electric field between cathode and anode accelerates the electrons, before they leave the electron gun through a small hole in the anode. • The electron beam can be deflected by a capacitor or coils in a way which causes it to display an image on the screen. The image may represent electrical waveforms (oscilloscope), pictures (television, computer monitor), echoes of aircraft detected by radar etc. • When electrons strike the fluorescent screen, light is emitted. • The whole configuration is placed in a vacuum tube to avoid collisions between electrons and gas molecules of the air, which would attenuate the beam. Flourescent screen Cathode Control grid Anode UA - 1 - CERN Teachers Lab Cathode ray tube Safety precautions • Don’t touch cathode ray tube and cables during operation, voltages of 300 V are used in this experiment! • Do not exert mechanical force on the tube, danger of implosions! ! Experimental procedure 1. -
Frequency Characteristics of the Electron-Tube Oscillation Generator
FREQUENCY CHARACTERISTICS OF THE ELECTRON—TUBE OSCILLATION GENERATOR BY RAY STUART QUICK B. S. University of California, 1916 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING IN THE GRADUATE SCHOOL OF THE! UNIVERSITY OF ILLINOIS 1919 UNIVERSITY OF ILLINOIS THE GRADUATE SCHOOL I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Hay Stuart 4uick ENTITLED Jgraqstaney Character i st.i cs of the Electron-Tube Oscillation Generator BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF Master of Snionoe in Eleotri nol Engin eering . \Mm Head of Department Recommendation concurred in :! Committee on Final Examination* *Required for doctor's degree but not for master's 1 CONTENTS I INTRODUCTION Page 1. Scope of work 2 2. Historical review. 2 II THEORETICAL DISCUSSION OP PROBLEM 1. General principles of operation. 4 2. Circuits used. 6 3. Work of previous investigators. 6 4. Mathematical solution of circuits. 8 III APPARATUS AND METHODS 1. Electron- tubes used. 13 2. Circuit properties. 13 3. Frenuency determinations. 13 IV DATA AND EXPERIMENTAL RESULTS 1. Observed conditions necessary for constant eurrent and for oscillating eurrent. 36 2. Oscillograms. 36 3. Experimental results. 37 V CONCLUSIONS 1. Comparison of experimental ^nd theoretical results. 45 2. Suggestions as to future work 45 VI BIBLIOGRAPHY 47 2 I INTRODUCTIOU 1. Scope of Work. The development of the electron- tube ( also called three-electrode vacuum tube, vacuum- tube, thermionic amplifier, audion, etc. ) has brought to light many new and interest- ing problems. In using the tube as a source of continuous oscilla- tions it is desirable to be able to predetermine the frequency, wave-form and amplitude characteristics. -
Photomultiplier Tube Basics Photomultiplier Tube Basics
Photomultiplier tube basics Photomultiplier tube basics Still setting the standard 8 Figures of merit 18 Single-electron resolution (SER) 18 Construction & operating principle 8 Signal-to-noise ratio 18 The photocathode 9 Timing 18 Quantum efficiency (%) 9 Response pulse width 18 Cathode radiant sensitivity (mA/W) 9 Rise time 18 Spectral response 9 Transit-time and transit-time differences 19 Transit-time spread, time resolution 19 Collection efficiency 11 Very-fast tubes 11 Linearity 19 Fast tubes 11 External factors affecting linearity 19 General-purpose tubes 11 Internal factors affecting linearity 20 Tubes optimized for PHR 12 Linearity measurement 21 Measuring collection efficiency 12 Stability 21 The electron multiplier 12 Long-term drift 21 Secondary emitting dynode coatings 13 Short-term shift (or count rate stability) 22 Voltage dividers 13 Gain 1 Supply and voltage dividers 23 Anode collection space 1 Applying the voltage 23 Anode sensitivity 1 Voltage dividers 2 Specifications and testing 1 Anode resistor 2 Maximum voltage ratings 1 Gain adjustment 2 Anode dark current & dark noise 1 Magnetic fields 2 Ohmic leakage 1 Thermionic emission 1 Magnetic shielding 27 Field emission 1 Environmental considerations 28 Radioactivity 1 Temperature 28 PMT without scintillator 1 Atmosphere 29 PMT with scintillator 1 Mechanical stress 29 Cathode excitation 1 Radiation 29 Dark current values on test tickets 1 Reference 30 Afterpulses 17 www.photonis.com Still setting Construction the standard & operating principle A photomultiplier tube is -
Vacuum Tubes BJT Or
Vacuum Tubes 3 Handouts Lab 3 (2) Lecture notes Linear without feedback Characteristics independent of temperature Wider dynamic range • Vacuum Tubes, BJT or FET? • • Circuit Analysis: Amplifier & Feedback NY Times – “Guitar heroes favor vacuum tube amplifiers in • Classic BJT Circuits their instruments” • Arduino Intro – “Many recording engineers tend to use vacuum‐ tube equipment in their studios” Acknowledgements: Yanni Coroneos, Henry Love – “Some listeners pay thousands of dollars for high‐ Neamen, Donald: Microelectronics Circuit Analysis and Design, 3rd Edition end tube‐based stereo systems and CD players.” 6.101 Spring 2020 Lecture 5 1 6.101 Spring 2020 Lecture 5 2 BJT or FET Transistor Configurations TRANSISTOR AMPLIFIER CONFIGURATIONS high input impedance, for voltage gain = 1 ; use low input impedance for low impedance general amplification +15V in amplifier output +15V +15V • Depends on application stage. sources, for high frequency response. R R • Amplifiers R L R R L BJT 2 2 2 + – BJT + + + + + + • are more linear that MOSFET, better fidelity (low harmonic + + + + + R + 1 VOUT VOUT V Vin R 1 RE V V in R OUT in R1 distortion) E RE - - • can drive low impedances at higher power - - - - • lower noise with low source impedance [a] Common Emitter Amplifier [b] Common Collector [Emitter Follower] Amplifier [c] Common Base Amplifier • Operate at < 2 V – MOSFET • high input impedance FET • Voltage controlled device => lower power Common gate Common drain [Source follower] Common source 6.101 Spring 2020 Lecture 5 3 6.101 Spring -
Unusual Tubes
Unusual Tubes Tom Duncan, KG4CUY March 8, 2019 Tubes On Hand GAS-FILLED HIGH-VACUUM • Neon Lamp (NE-51) • Photomultiplier • Cold-cathode Voltage (931A) Regulator (0B2) • Magic Eye (1629) • Hot-cathode Thyratron • Low-voltage (12DY8) (884) • Space Charge (12K5) 2 Timeline of Related Events 1876, 1902 William Crookes Cathode Rays, Glow Discharge 1887 [1921] Hertz, Einstein Photoelectric Effect 1897 [1906] J. J. Thomson Electron identified 1920 Daniel Moore (GE) Voltage Regulator 1923 Joseph Slepian Secondary Emission (Westinghouse) 1928 Albert Hull, Irving Thyratron Langmuir (GE) [1928] Owen Richardson Thermionic Emission 1936 Vladimir Zworykin Photomultiplier (RCA) 1937 Allen DuMont Magic Eye 3 Neon Bulbs • Based on glow-discharge (coronal discharge) effect noticed by William Crookes around 1902. • Exhibit a negative incremental resistance over part of the operating range. • Light-sensitive: photo-ionization causes the ionization voltage to decrease with illumination (not generally a desirable characteristic). • Used as indicators , voltage regulators, relaxation oscillators , and the larger ones for illumination . 4 Neon Lamp/VR Tube Curves 80 Normal Abnormal Glow Glow 70 60 Townsend Discharge 50 Negative Resistance 40 Region 30 Volts across Device across Volts 20 10 Conduction Destroys Lamp Destroys Arc Conduction Arc Chart details (coronal) Glow depend on -5 element 10 -20 10 -15 10 -10 10 1 geometry and Current through Device (A) gas mixture. 5 Cold-Cathode Voltage Regulator Tubes • Very similar to neon bulbs: attention paid to increasing current-carrying capability and ensuring a constant forward voltage. • Gas sometimes includes radio-isotopes to reduce sensitivity to photo-ionization. • Developed at General Electric Research Labs by Daniel Moore around 1920.