Silicon Controlled Rectifier (SCR) PDF

SILICON CONTROLLED RECTIFIER (SCR) ANTONIO LUIS B. SADONGDONG SEP.3,2024 HOLY FAITH S. CATUGAL AAM103 – INDUSTRIAL ELECTRONINCS SILICON CONTROLLED RECTIFIER (SCR) IS A UNIDIRECTIONAL SEMICONDUCTOR DEVICE MA...

SILICON CONTROLLED RECTIFIER (SCR) ANTONIO LUIS B. SADONGDONG SEP.3,2024 HOLY FAITH S. CATUGAL AAM103 – INDUSTRIAL ELECTRONINCS SILICON CONTROLLED RECTIFIER (SCR) IS A UNIDIRECTIONAL SEMICONDUCTOR DEVICE MADE OF SILICON. IT HAS A FOUR-LAYER OF ALTERNATING P-TYPE AND N-TYPE MATERIAL AND A THREE-TERMINAL DEVICE (ANODE, CATHODE, GATE) SOLID-STATE CURRENT-CONTROLLING DEVICE THAT IS EQUIVALENT TO A THYRISTOR. TAKE NOTE: SCR IS A TRADE NAME OF GENERAL ELECTRIC TO THE THYRISTOR HOW IT WORKS? STRUCTURE AND SYMBOLS STRUCTURE AND SYMBOLS J1 J2 J3 THREE MODES OF OPERATION FOR AN SCR DEPENDING UPON THE BIASING GIVEN TO IT: REVERSE BLOCKING MODE (OFF STATE) FORWARD BLOCKING MODE (OFF STATE) FORWARD CONDUCTION MODE (ON STATE)  REVERSE BLOCKING MODE (OFF STATE) P N DEPLETION REGION P N  FORWARD BLOCKING MODE (OFF STATE) P N DEPLETION REGION P N  FORWARD CONDUCTION MODE (ON STATE) GATE TRIGGER  FORWARD CONDUCTION MODE (LATCHING) PURPOSE ADVANTAGES OF SCR 1.High Power Handling 2.Efficient Switching 3.Controlled Firing 4.Thermal Stability 5.Durability 6.Cost-Effective  High Power Handling: SCRs can handle high voltages and currents, making them suitable for power control and switching applications. Efficient Switching: They provide efficient switching with minimal power loss when in the on-state, which is advantageous for power control. Controlled Firing: SCRs can be turned on by a gate signal, allowing precise control over their operation.  Thermal Stability: They have good thermal stability and can operate over a wide temperature range. Durability: SCRs are robust and durable, with a long operational lifespan under proper conditions. Cost-Effective: They are relatively inexpensive compared to other high-power semiconductor devices. DISADVANTAGES OF SCR 1. Unidirectional Conductivity 2. Triggering Requirement 3. Latching 4. Complexity in Switching Off 5. Sensitive to Overvoltage  Unidirectional Conductivity: SCRs allow current to flow only in one direction, which limits their use in certain applications. Triggering Requirement: SCRs require a gate signal to trigger conduction, which adds complexity to the control circuitry. Latching: Once an SCR is triggered on, it remains on until the current through it drops below a certain level (holding current). This latching behavior can be a drawback in circuits that require frequent or precise switching.  Complexity in Switching Off: Turning off an SCR requires reducing the current below its holding level or using additional circuitry, which can complicate design. Sensitive to Overvoltage: SCRs can be sensitive to overvoltage conditions, which may lead to damage if not properly managed. DIFFERENCES OF SCR TO OTHER COMPONENTS  SHOCKLEY DIODE & SCR The Shockley diode and Silicon Controlled Rectifier (SCR) are both semiconductor devices used in electronics, but they have different structures and functions. Shockley Diode: Silicon Controlled Rectifier (SCR): A Shockley diode is a type of four-layer diode (p-n-p-n An SCR is also a four-layer device structure). (p-n-p-n structure). It has three It has two terminals: anode and terminals: anode, cathode, and gate. It is designed to control power flow, cathode. It acts like a regular diode acting as a switch that a small gate but has a threshold voltage that current can turn on. Once turned on, it must be reached for it to conduct. remains on as long as there is a Once it starts conducting, it current flow above the holding current. continues until the current drops It turns off when the current falls below a certain level, known as the below this level or if the circuit is holding current. reset.  Difference between SCR AND SCS SCR (Silicon Controlled SCS (Silicon Controlled Rectifier): Switch): A four-layer semiconductor Similar to an SCR but with four device with three terminals terminals (anode, cathode, gate, (anode, cathode, and gate). It and anode gate). It provides acts as a switch that remains off more control, allowing the device until a gate signal is applied and to be turned on and off through stays on until the current drops the gate and anode gate below a threshold. terminals. APPLICATIONS OF SCR SCRs are mainly used in devices that require high power control, sometimes alongside high voltage. They can be used in medium- to high-voltage AC power control applications because of the way they operate. SOME MAIN APPLICATIONS OF SCR: SPEED CONTROLS LIGHT DIMMERS RECTIFIER CIRCUITS AND; USED MAINLY IN AC MOTORS, LIGHTS, WELDING MACHINE, ETC.  REFERENCES Moll, J.; Tanenbaum, M.; Goldey, J.; Holonyak, N. ^ Christiansen, Donald; Alexander, Charles; (September 1956). "P-N-P-N Transistor Jurgen, Ronald (2005). Standard Handbook of Switches". Proceedings of the IRE. 44 (9): Electronic Engineering, 5th Edition. 1174–1182. doi:10.1109/jrproc.1956.275172. ISSN 0096 Mcgraw-hill. ISBN 9780071384216. -8390. S2CID 51673404. ^ International Electrotechnical ^ Vasseur, J. P. (2016-06-06). Properties and Commission 60747-6 standard Applications of Transistors. ^ Dorf, Richard C. (1997-09-26). The Electrical Elsevier. ISBN 9781483138886. Engineering Handbook, Second Edition. CRC ^ Twist, Jo (2005-04-18). "Law that has driven digital Press. ISBN 9781420049763. life". BBC News. Retrieved 2018-07-27. ^ Ward, Jack. "The Early History of the Silicon ^ Ward, Jack. "The Early History of the Silicon Controlled Rectifier". p. 7. Retrieved 12 Controlled Rectifier". p. 6. Retrieved 12 April 2014. April 2014. ^ "Semiconductors: Thyristors and more". Edison Tech ^ Mohan, Ned (2012). Power Electronics: A First Center. Course. United States: Don Fowley. ^ "SCR is 50 Years Old" (PDF). IEEE Industry pp. 230–231. ISBN 978-1-118-07480-0. Applications Magazine. ^ Mungenast, J. E. "The SCR Revolution". RF Cafe. General Electric Co. YouTube Clips References https://www.youtube.com/watch?v=AhFDWfFjdOE&list=PL096Sxqg8PZaPR OdTvLG0LvCfCPjv2m-m https://www.youtube.com/watch?v=8OgHY4-gcQw&list=PL096Sxqg8PZaPR OdTvLG0LvCfCPjv2m-m&index=2 https://www.youtube.com/watch?v=jIA3fs9rF50&list=PL096Sxqg8PZaPROd TvLG0LvCfCPjv2m-m&index=3 https://www.youtube.com/watch?v=KqH1GzeoiMY&list=PL096Sxqg8PZaPR OdTvLG0LvCfCPjv2m-m&index=4 https://www.youtube.com/watch?v=0AgPUikpvpM&t=16s https://www.youtube.com/shorts/LNFALYiwQn8