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Module 4 thyristors


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This slide is part of the material used to prepare the students for Module 4 of EASA part 66 examination for License category B1

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Module 4 thyristors

  1. 1. Thyristors
  2. 2. Characteristics Hysteresis character ◦ It latches to its last position, on or off ◦ Example, physical s/w – you s/w it on, it remains on. May be viewed as 2 transistors working in pair. Constructed from bipolar junction technology.
  3. 3. Examples of Thyristors Shockley diode DIAC SCR (silicon controlled rectifier) TRIAC Opto thyristors
  4. 4. Shockley Diode Not to be confused with schottky diode It is a four layer device Also known as PNPN diode.
  5. 5. The Working of the ShockleyDiode The four PNPN can be simplified to two set of separate transistors, PNP and NPN. P N P N P N
  6. 6. With high voltage, one of the transistor will be turnedon causing the other to be on. Once on, thetransistors latched. To turn off, the voltage must bereduced to cause the current to drop below minimum
  7. 7. DIAC Shockley diode works with DC. For AC, 2 shockleys are joint. The result is shown in the lower image
  8. 8. SCR Silicon Controlled Rectifiers or thyristors. Used to rectify AC and control the power output.
  9. 9. TRIAC Dimmer
  10. 10. TRIAC FOR AC
  11. 11. Opto- tyristors
  12. 12. RESOURCESMy Blog CAA UK Recommended Books Title Author Aircraft Electricity and Eisman 0-02-801859-1 Electronics Art of Electronics Horowitz 0-521-37095-7 Horowitz /Hill /Hill Elements of Hickey/ 0070286957 Electronics Villines Modern Aviation Helfrich 0-13-118803-8 Electronics Micro Electronics in E Pallet 0-273-08612-X Aircraft systems