Edit Proposal: Milestone-Proposal:SCR/Thyristor You do not have permission to edit this page, for the following reason: You are not currently logged in. The action you have requested is limited to users in the group: Users. Please log in or create an account. Docket ID: (admins only) Thank you for proposing a technical achievement for possible recognition as an IEEE Milestone in Electrical Engineering and Computing. Your efforts help preserve the heritage of technology. Detailed information on the Milestone application process may be found at: Milestone Guidelines and How to Propose a Milestone. At least one of the proposer(s) must be an IEEE Member (including Student Member) in good standing. To the proposer’s knowledge, is this achievement subject to litigation? If the answer is "yes", the proposal cannot proceed further. Yes No You must be able to answer "yes" to all of the following questions. If the answer to any of the following questions is "no", the proposal cannot proceed further. Contact us at firstname.lastname@example.org if you are unable to answer "yes" to all of the following and would still like to proceed. Is the achievement you are proposing more than 25 years old? Yes No Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes No Did the achievement provide a meaningful benefit for humanity? Yes No Was it of at least regional importance? Yes No Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes No Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes No Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes No Has the owner of the site given permission to place an IEEE plaque? Yes No Year or range of years in which the achievement occurred: Title of the proposed milestone. (Include date or date range in title. Example: “Alternating Current Electrification, 1886”) Please provide a plaque citation in English summarizing the achievement and its significance. Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons. NOTE: The IEEE History Committee shall have final determination on the wording of the citation. Names of living persons are not normally used in citations. Exceptions to this are cases where the person's name is linked to the achievement itself (e.g. the Lempel-Ziv algorithm, Maxwell's Equations, etc.) or where the person's name is so widely recognizeable to the general public that it makes sense to use it. When used, the names should be the names of the engineers, scientists, or technologists who actually made the achievement, rather than managers or executives. For more information and suggestions about writing milestone citations, please visit Helpful Hints on Citations, Plaque Locations. General Electric introduced the silicon controlled rectifier (SCR), a three-terminal p-n-p-n device, in 1957. The gas-filled tubes used previously were difficult to operate and unreliable. The symmetrical alternating current switch (TRIAC), the gate turn-off thyristor (GTO), and the large integrated gate-commutated thyristor (IGCT) evolved from the SCR. Its development revolutionized efficient control of electric energy and electrical machines. In what IEEE section(s) will the milestone plaque(s) reside? Please specify the IEEE Organizational Unit(s) which have agreed to sponsor the Milestone, and supply name and contact information for the senior officer from those OU(s). Sponsorship has three aspects: 1) Payment for the cost of the plaque(s), 2) Arranging the dedication ceremony, and 3) agreeing to monitor the plaque and to let IEEE History Center staff know in case the plaque needs to be moved, is no longer secure, etc. Number 3 must be done by the IEEE Section(s) in which the plaque(s) is located, but aspects 1 and 2 can be done by any IEEE Organizational Unit, and they need not be the same one. Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address. IEEE Organizational Unit(s) paying for milestone plaque(s) Unit: Senior Officer Name: E-mail: Unit: Senior Officer Name: E-mail: IEEE Organizational Unit(s) arranging the dedication ceremony Unit: Senior Officer Name: E-mail: Unit: Senior Officer Name: E-mail: IEEE section(s) monitoring the plaque IEEE Section: IEEE Section Chair name: IEEE Section Chair e-mail: IEEE Section: IEEE Section Chair name: IEEE Section Chair e-mail: Milestone proposer(s) Proposer name: Proposer email: Proposer name: Proposer email: Street address(es) and GPS coordinates of the intended milestone plaque site(s). Please include coordinates in decimal format rather than degrees. What is the intended site(s) of the milestone plaque(s) relation to the achievement? The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque. Also, please Describe briefly the intended site(s) of the milestone plaque(s). (e.g. Is it corporate buildings? Historic Site? Residential? Are there other historical markers already at the site?) Are the original buildings extant? Please provide the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. How is the intended plaque site protected/secured, and in what ways is it accessible to the public? If visitors to the plaque site will need to go through security, or make an appointment, please give details as well as the contact information visitors will need in order to arrange to visit the plaque. Who is the present owner of the site(s)? In the space below, please describe in detail: the historic significance of the achievement, its importance to the evolution of electrical and computer engineering and science, its importance to regional/national/international development, its benefits to humanity, the ways the achievement was a significant advance rather than an incremental improvement of existing technology. The material submitted here will constitute the main descriptive article on the ETHW website for readers to learn about the milestone. Space is unlimited, and detail is encouraged. Most milestones require 1000 to 1500 words of support, however there is no word limit. The article should be readable by a wide audience that includes practicing engineers, scholars of history, and the general public. Some examples of the text of good milestone articles are First Radio Astronomical Observations Using Very Long Baseline Interferometry] and G3_Facsimile International Standardization of G3 Facsimile (Do not worry about the formatting of the page, IEEE History Center Staff will do that afterwards.) What is the historical significance of the work (its technological, scientific, or social importance)? The invention of the SCR/Thyristor revolutionized the control of electric power conversion by replacing the gas-filled controlled rectifier tube (the thyratron) with a three-terminal solid-state device consistiing of an anode, a cathode and a gate. Unlike the two terminal diode in which current flows when a positive voltage is applied between the anode and the cathode, the SCR will not conduct with a positive anode-cathode voltage until a small voltage is applied between the gate and the cathode. Conduction is stopped by reducing the current to a low value known as the latching current. The invention of the SCR/Thyristor led to dramatic efficiency and control improvements in the rectification of line voltages and is the basis of modern speed control of ac and dc motors. Its application to motor control had a substantial impact in electric traction, making possible the displacement of dc motors by the more efficient and reliaable ac motors, particlulaly in railroads. The SCR and its derivative, the GTO, have made possible HVDC transmission at much higher voltages and power levels than previously obtainable with mercury arc rectifiers and thyratrons. The SCR has also had a dramatic impact on manufacturing.The steel, electrochemical, automotive and welding industries, among many others, benefited greaatly by the improved efficiency, more precise control, and reduced cost made possible by the application of SCR based equipment to their processes. What obstacles (technical, political, geographic) needed to be overcome? The functional basis of the SCR as an interconnection of two transistors was originally described as early as 1950 and published by J. J. Ebers of Bell Laboratories in 1952. The subsequent reduction to practice as a monolithic device required a deeper understanding of the current dependency of the current gains of the two transistors, and recognition that silicon and not germanium was the appropriate semiconductor to use. Problems of false triggering by thermally or dv/dt induced currents at the triggering junction also needed to be understood and solved. Initial devices demonstrated relatively low power ratings, leading some to believe that the SCR was not destined for high power applications. Improvements in silicon crystal growth and wafer processing lead to ever larger devices with ratings now exceeding 10 kV and 3 kA. Package design was another challenge as device ratings, and hence device dissipation, increased. The single-sided cooled, stud mounted device was replaced by the two-sided cooled “hockey puck” package in which the silicon was not bonded, but contacted by compression of the package thus allowing movement to accommodate thermally induced stresses in the large Si wafer. A further obstacle to extending the application of the SCR is the speed at which it is capable of switching. Early devices could be applied at frequencies not much higher than 10’s of Hz. A better understanding of device behavior and Improvements in device design and fabrication have produced devices capable of operating at frequencies in the 10’s of kHz. What features set this work apart from similar achievements? Among similar achievements are the thyratron, the bipolar transistor (BJT) and the field effect transistor (FET), devices which were invented before the SCR. The SCR made the thyratron obsolete by manifesting it’s function in a smaller, more efficient, more reliable and more easily controlled solid state device. In addition, the SCR can exhibit power ratings far exceeding the thyratron’s. Besides its ability to control much higher power levels, the singular feature of the SCR that sets it apart from the BJT and FET is its bipolar voltage blocking capability. The BJT can support a voltage of only one polarity and thus cannot function in applications for which the SCR is appropriate. Due to materials issues the FET had a long gestation period before it became a practical device, and it wasn’t until the 1970’s that the vertical channel power MOSFET was developed. Like the BJT, the FET is incapable of bilateral voltage blocking and cannot be used in place of the SCR. Supporting texts and citations to establish the dates, location, and importance of the achievement. You must supply the texts or excerpts themselves, not just the references. Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. At least one of the references must be from a scholarly book or journal article. 'Scholarly' is defined as peer-reviewed, with references, and published. The full reference, in English, must be uploaded, not just the citation. See below section for details on uploading material to the website. All supporting materials must be in English, or accompanied by an English translation.  [[Media:Milestone Reference 1-SCR 50 Yrs Old Owen IASMag 2007.pdf|E. L. Owen, "SCR Is 50 Years Old"]], IEEE Industry Applications Magazine, Volume 13, Issue 6, Pages 6 - 10, 2007  [[Media:Milestone Reference 2-The Silicon pnpn Switch Holonyak 2001.pdf|N. Holonyak]], "The Silicon p-n-p-n Switch and Controlled Rectifier (Thyristor)",IEEE Transactions on Power Electronics, Volume 16, Issue 1, Pages 8 - 16, 2001  [[Media:Ref1 Tiku 2014 IEEE PE Magazine.pdf|Deepak Tiku,, "dc Power Transmission: Mercury-Arc to Thyristor HVdc Valves",]] IEEE Power and Energy Magazine, Volume 12, Issue: 2 Pages: 76 - 96, 2014  [[Media:Milestone Reference 4-Uno Lamm the father of HVdc transmission.pdf|M. Korytowski, "Uno Lamm the father of HVdc transmission"]], IEEE Power and Energy Magazine, Volume 15, Issue:3 Pages: 92-102, 2017  [[Media:Milestone Reference 5-GE - SCR Manual 1964.pdf|GE SCR Manual, 5th Ed.]], GE Syracuse New York, 1972 Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC) which can be made publicly available on the IEEE History Center’s website (i.e. unencumbered by copyright, or with the copyright holder’s permission). All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. Images and photographs are especially appreciated, however, it is necessary that you list the copyright owner for these and obtain the copyright owner’s permission to reuse. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to email@example.com. Please see the Milestone Program Guidelines for more information. To add attachments, first upload the file and add by adding the text: [[Media:(filename)]] For example, if the file you uploaded was named "Milestone Reference.pdf", include the text: [[Media:Milestone Reference.pdf]] in the appropriate field. Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to firstname.lastname@example.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s). Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished Summary: This is a minor edit Watch this page Cancel Retrieved from "http://ieeemilestones.ethw.org/Milestone-Proposal:SCR/Thyristor"