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THYRISTORS Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. Thyristors Thyristors are a class of semiconductor devices characterized by 4-layers of alternating p and n material. Four-layer devices act as either open or closed switches; for this reason, they are most frequently used in control applications. Some thyristors and their symbols are (a) 4-layer diode (b) SCR (c) Diac (d) Triac (e) SCS Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. The Four-Layer Diode The 4-layer diode (or Shockley diode) is a type of thyristor that acts something like an ordinary diode but conducts in the forward direction only after a certain anode to cathode voltage called the forward-breakover voltage is reached. The basic construction of a 4-layer diode and its schematic symbol are shown The 4-layer diode has two leads, labeled the anode (A) and the Anode (A) A cathode (K). p 1 n The symbol reminds you that it acts 2 p like a diode. It does not conduct 3 when it is reverse-biased. n Cathode (K) K Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. The Four-Layer Diode The concept of 4-layer devices is usually shown as an equivalent circuit of a pnp and an npn transistor. Ideally, these devices would not conduct, but when forward biased, if there is sufficient leakage current in the upper pnp device, it can act as base current to the lower npn device causing it to conduct and bringing both transistors into saturation. -
68 Chapter 9: Thyristors Thyristors Thyristors Are a Class Of
Electronic Devices Chapter 9: Thyristors Thyristors Thyristors are a class of semiconductor devices characterized by 4-layers of alternating p- and n-material. Four-layer devices act as either open or closed switches; for this reason, they are most frequently used in control applications such as lamp dimmers, motor speed controls, ignition systems, charging circuits, etc. Thyristors include Shockley diode, silicon-controlled rectifier (SCR), diac and triac. They stay on once they are triggered, and will go off only if current is too low or when triggered off. Some thyristors and their symbols are in figure 1. (a) 4-layer diode (b) SCR (c) Diac (d) Triac (e) SCS Figure 1 Shockley Diode The 4-layer diode (or Shockley diode) is a type of thyristor that acts something like an ordinary diode but conducts in the forward direction only after a certain anode to cathode voltage called the forward-breakover voltage is reached. The basic construction of a 4-layer diode and its schematic symbol are shown in Figure 2. Figure 2: The 4-layer diode. The 4-layer diode has two leads, labeled the anode (A) and the cathode (K). The symbol reminds you that it acts like a diode. It does not conduct when it is reverse-biased. The concept of 4-layer devices is usually shown as an equivalent circuit of a pnp and an npn transistor. Ideally, these devices would not conduct, but when forward biased, if there is sufficient leakage current in the upper pnp device, it can act as base current to the lower npn device causing it to conduct and bringing both transistors into saturation 68 Assist. -
The Transistor
Chapter 1 The Transistor The searchfor solid-stateamplification led to the inventionof the transistor. It was immediatelyrecognized that majorefforts would be neededto understand transistorphenomena and to bring a developedsemiconductor technology to the marketplace.There followed a periodof intenseresearch and development, duringwhich manyproblems of devicedesign and fabrication, impurity control, reliability,cost, and manufacturabilitywere solved.An electronicsrevolution resulted,ushering in the eraof transistorradios and economicdigital computers, alongwith telecommunicationssystems that hadgreatly improved performance and that were lower in cost. The revolutioncaused by the transistoralso laid the foundationfor the next stage of electronicstechnology-that of silicon integratedcircuits, which promised to makeavailable to a massmarket infinitely more complexmemory and logicfunctions that could be organizedwith the aid of softwareinto powerfulcommunications systems. I. INVENTION OF THE TRANSISTOR 1.1 Research Leading to the Invention As World War II was drawing to an end, the research management of Bell Laboratories, led by then Vice President M. J. Kelly (later president of Bell Laboratories), was formulating plans for organizing its postwar basic research activities. Solid-state physics, physical electronics, and mi crowave high-frequency physics were especially to be emphasized. Within the solid-state domain, the decision was made to commit major research talent to semiconductors. The purpose of this research activity, according -
SHOCKLEY, WILLIAM BRADFORD Els at Which Electrons Can (Or Cannot) Flow Through a Crys- (B
ndsbv6_S2 9/27/07 4:14 PM Page 437 Shockley Shockley Greenstein, Jesse, and Rudolph Minkowski. “The Crab Nebula John Bardeen and Walter Brattain, he invented the tran- as a Radio Source.” Astrophysical Journal 118 (1953): 1–15. sistor, sharing the 1956 Nobel Prize in Physics with them McCutcheon, Robert A. “Stalin’s Purge of Soviet Astronomers.” for this achievement. In particular, he conceived the junc- Sky & Telescope 78, no. 4 (October 1989): 352–357. tion transistor, a solid-state amplifier and switch that was Minkowski, Rudolph. “The Crab Nebula.” Astrophysical Journal commercialized during the 1950s and eventually led to 96 (1942): 199–213. Reprinted with commentary in A the microelectronics revolution. In founding the Shockley Source Book in Astronomy & Astrophysics, edited by Kenneth Semiconductor Laboratory in California, he catalyzed the R. Lang and Owen Gingerich. Cambridge, MA: Harvard University Press, 1979. emergence of Silicon Valley as the epicenter of the global semiconductor industry. As a Stanford University profes- Moroz, Vasilii I. “A Short Story about the Doctor.” Astrophysics & Space Science B252 (1997): 1–2, 5–14. sor during the last two decades of his life, he espoused Oort, Jan H. “The Crab Nebula.” Scientific American 196, no. 3 controversial views on race and intelligence that brought (March 1957): 52–60. On Shklovskii’s hypothesis of him substantial public attention and notoriety. synchrotron radiation as the source of its emission. Salomonovich, A. E. “The First Steps of Soviet Radio Early Years. Shockley was born in London on 13 Febru- Astronomy.” In The Early Years of Radio Astronomy: Reflections ary 1910, the only son of William Hillman Shockley, a Fifty Years after Jansky’s Discovery, edited by W. -
Questions for Electronics
www.YoYoBrain.com - Accelerators for Memory and Learning Questions for electronics Category: Default - (192 questions) What electronic device is a breakover diode diac made to trigger triacs in phase-controlled circuits 3 basic options for converting single phase to static, rotary, and electronic 3 phase power Define: static phase converter simplest/lowest cost option for converting single to 3 phase electricity Nothing more than a capacitor and a potential relay comprising a starter circuit Define: rotary phase converter consists of a 3-phase motor and some way of starting it, be it a rope and pulley or a well-designed static converter automatic start circuit converts single phase to 3 phase electricity Define: variable frequency drive a box of solid-state electronics that convert 3-phase 60 Hz AC to variable frequency 3-phase. Allows motors to be driven at different speeds Define: polarized plug a plug that must be plugged in correctly to reference line on ac plug or it will harm the equipment Define: Shockley diode special purpose diode with more 2 PN junctions (four-layer diode) uses a trigger voltage to switch the diode on What is the purpose of SSIFET transistors used in microwave frequency circuits Define: latching relay a relay where one control pulse closes the switch contacts and it remains closed until another signal tells it to release Define: component placement diagram used to show where components are layed out on circuit board Define: cold solder joints a rough and grainy solder joint; source of many problems on circuits -
Oral History of Hans Queisser
Oral History of Hans Queisser Interviewed by: Craig Addison Recorded: February 27, 2006 Mountain View, California CHM Reference number: X3453.2006 © 2006 Computer History Museum Oral History of Hans Queisser Craig Addison: I am Craig Addison from SEMI. I am with Hans Queisser. We’re at the Computer History Museum in Mountain View, California, and today’s date is February 27, 2006. Hans, could we start off at the beginning and have you talk about where you were brought up and your educational background. Hans Queisser: Yes. I was born in Berlin, Germany, in 1931. My father was an engineer with the Siemen’s Company. And at that time, Siemen’s Town in Berlin was really a center of high technology. So I got very much influenced by my father, by our neighbors, in technical things. And I survived the Dresden air raid just barely in 1945 when I was 14 years old. And the end of the war was not easy, you can imagine. My father had to work for a Russian government agency. Times were tough. And my belief that I should enter a scientific field was strengthened by the fact that I could see that people who had a technical background and who had something to say, were treated very nicely by both the Russians and the Americans. But people who had nothing of value were treated rather badly. So that was my belief that in order to survive you had to have something that was a skill. And I wanted to go into physics, which I did. -
Teccor® Brand Thyristors Qxxxxltx Series
Teccor® brand Thyristors 4 / 6 / 8 / 10 / 15 Amp Quadracs QxxxxLTx Series RoHS ® Description The Quadrac is an internally triggered Triac designed for AC switching and phase control applications. It is a Triac and DIAC in a single package, which saves user expense by eliminating the need for separate Triac and DIAC components. Standard type devices normally operate in Quadrants I & III triggered from AC line. Alternistor type Quadracs are used in circuits requiring high dv/dt capability. Features & Benefits Agency Approval • RoHS Compliant • Surge capability up to 200 A • Glass – passivated Agency Agency File Number junctions ® L Package : E71639 • Voltage capability up to 600 V Schematic Symbol Applications Excellent for AC switching and phase control applications such as lighting and heating. Typical applications are AC MT2 MT1 solid-state switches, light dimmers, power tools, home/ brown goods and white goods appliances. T Alternistor Quadracs (no snubber required) are used in applications with extremely inductive loads requiring highest commutation performance. Main Features Internally constructed isolated package is offered for ease Symbol Value Unit of heat sinking with highest isolation voltage. IT(RMS) 4 to 15 A VDRM / VRRM 400 to 600 V Additional Information DIAC VBO 33 to 43 V Datasheet Resources Samples © 2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor® brand Thyristors 4 / 6 / 8 / 10 / 15 Amp Quadracs Absolute Maximum Ratings Value Symbol Parameter Unit Qxx04LT Qxx10LT / -
The Silicon Controlled Rectifier (SCR)
The silicon controlled rectifier (SCR) Shockley diodes are curious devices, but rather limited in application. Their usefulness may be expanded, however, by equipping them with another means of latching. In doing so, each becomes true amplifying devices (if only in an on/off mode), and we refer to these as silicon-controlled rectifiers, or SCRs. The progression from Shockley diode to SCR is achieved with one small addition, actually nothing more than a third wire connection to the existing PNPN structure: (Figure below) The Silicon-Controlled Rectifier (SCR) If an SCR's gate is left floating (disconnected), it behaves exactly as a Shockley diode. It may be latched by breakover voltage or by exceeding the critical rate of voltage rise between anode and cathode, just as with the Shockley diode. Dropout is accomplished by reducing current until one or both internal transistors fall into cutoff mode, also like the Shockley diode. However, because the gate terminal connects directly to the base of the lower transistor, it may be used as an alternative means to latch the SCR. By applying a small voltage between gate and cathode, the lower transistor will be forced on by the resulting base current, which will cause the upper transistor to conduct, which then supplies the lower transistor's base with current so that it no longer needs to be activated by a gate voltage. The necessary gate current to initiate latch-up, of course, will be much lower than the current through the SCR from cathode to anode, so the SCR does achieve a measure of amplification. -
Silicon-Controlled Rectifiers
Component Theory SCRs 1 Silicon-Controlled Rectifiers Our exploration of thyristors begins with a device called the four-layer diode, also known as a PNPN diode, or a Shockley diode after its inventor, William Shockley. This is not to be confused with a Schottky diode, that two-layer metal-semiconductor device known for its high switching speed. A crude illustration of the Shockley diode, often seen in textbooks, is a four-layer sandwich of P-N-P-N semiconductor material. 2 Silicon-Controlled Rectifiers Shockley or 4-layer diode Transistor equivalent of Shockley diode 3 Silicon-Controlled Rectifiers A silicon-controlled rectifier (or semiconductor- controlled rectifier) is a four-layer solid state device that controls current. The name "silicon controlled rectifier" or SCR is General Electric's trade name for a type of thyristor. The SCR was developed by a team of power engineers led by Gordon Hall and commercialized by Frank W. "Bill" Gutzwiller in 1957. 4 Silicon-Controlled Rectifiers Construction of SCR An SCR consists of four layers of alternating P and N type semiconductor materials. Silicon is used as the intrinsic semiconductor, to which the proper dopants are added. The junctions are either diffused or alloyed. The planar construction is used for low power SCRs (and all the junctions are diffused). The mesa type construction is used for high power SCRs. In this case, junction J2 is obtained by the diffusion method and then the outer two layers are alloyed to it, since the PNPN pellet is required to handle large currents. 5 Silicon-Controlled Rectifiers It is properly braced with tungsten plates to provide greater mechanical strength. -
Catalogo Tiristor
Thyristor Product Catalog Teccor Electronics 1800 Hurd Drive Irving, Texas 75038 United States of America Phone: +1 972-580-7777 Fax: +1 972-550-1309 Website: http://www.teccor.com E-mail: [email protected] ©2002 Teccor Electronics i http://www.teccor.com Thyristor Product Catalog +1 972-580-7777 Teccor Electronics reserves the right to make changes at any time in order to improve designs and to supply the best products possible. The information in this catalog has been carefully checked and is believed to be accurate and reliable; however, no liability of any type shall be incurred by Teccor for the use of the circuits or devices described in this publication. Furthermore, no license of any patent rights is implied or given to any purchaser. Teccor Electronics is the proprietor of the QUADRAC® trademark. is a registered trademark of Underwriters Laborato- ries, Inc. All other brand names may be trademarks of their respective companies. To conserve space in this catalog, the trademark sign (®) is omitted. http://www.teccor.com ii ©2002 Teccor Electronics +1 972-580-7777 Thyristor Product Catalog Contents Product Selection Guide Product Descriptions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - vi Circuit Requirement Diagram - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - vii Product Packages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - viii Description of Part Numbers- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - x Quality -
Physics of Semiconductor Devices – Chapter 4: Thyristors
Physics of Semiconductor Devices – Chapter 4: Thyristors • 4.1: Introduction • 4.2: Basic characteristics • 4.3: Shockley diode and three-terminal thyristor • 4.4: Related power thyristors • 4.5: Diac and triac • 4.6: Unijunction transistor and trigger thyristor • 4.7: Field-controlled thyristor Student presentations 2006-04-05 Ulf Lindefelt, ITM, MIUN 1 4.1: Introduction • The word “thyristor” comes from the word “gas thyratron”, which was an old- fashioned gas-based device having roughly the same electrical characteristics as the semiconductor-based thyristor. • Basically, a thyristor is a switch which has a forward high impedance low current OFF state and a forward low impedance high current ON state. • In general terms a thyristor is a semiconductor device of the type pnpn or npnp, i.e., a four-layer device. A two-terminal thyristor is often called a Shockley diode. • A theoretical description of how a thyrisor works was developed by Moll et al. (J.L. Moll, M. Tanenbaum, J.M. „Goldley and N. Holonyak, “p-n-p-n Transistor Switches”, Proc. IRE 44, 1174 (1956)). • It is typically used in the high voltage, high current regime (typically 10 kV, 5kA) 2006-04-05 Ulf Lindefelt, ITM, MIUN 2 4.2: Basic characteristics Shockley diode Fig.2a: Typical doping profiles in Thyristor a thyristor In these lectures I use the term „thyristor‟ to denote also the „Shockley diode‟ 2006-04-05 Ulf Lindefelt, ITM, MIUN 3 4.2: Basic characteristics • (0)-(1): Forward blocking (or OFF) state • (1): Forward breakover (at breakover voltage VBF and switching current -
Pn JUNCTION DEVICES and LIGHT EMITTING DIODES
pn Junction Devices (© 2001 S.O. Kasap) 1 An e-Booklet pn JUNCTION DEVICES AND LIGHT EMITTING DIODES Safa Kasap Electrical Engineering Department University of Saskatchewan Canada “We consider alloyed or point contact junctions on n-type GaP. Then the light emitted with forward bias has a spectrum which is a comparatively narrow band, the position of the band depending on the impurities present in the GaP.” J.W. Allen and P.E. Gibbons (1959)1 William Shockley, (seated), John Bardeen (left) and Walter Brattain (right) invented the transistor at Bell Labs and thereby ushered in a new era of semiconductor devices. The three inventors shared the Nobel prize in 1956. (Courtesy of Bell Laboratories.) 1. pn Junction Principles 1. 1. Open Circuit Consider what happens when one side of a sample of Si is doped n-type and the other p-type as shown in Figure 1 (a). Assume that there is an abrupt discontinuity between the p and n regions which we call the metallurgical junction, M in Figure 1 (a), where the fixed (immobile) ionized donors and the free electrons (in the conduction band, CB) in the n-region and fixed ionized acceptors and holes (in the valence band, VB) in the p-region are also shown. 1 Allen and Gibbons (talking about their invention of the LED) in “Breakdown and light emission in gallium phosphide diodes”, Journal of Electronics, Vol. 7, No. 6, p. 518, December 1959. pn Junction Devices (© 2001 S.O. Kasap) 2 An e-Booklet Due to the hole concentration gradient from the p-side, where p = ppo, to the n-side where p = pno, holes diffuse towards the right and enter the n-region and recombine with the electrons (majority carriers) in this region.