2. الثايرستور Thyristor

8. Anode (Aluminum) Cathode P n P Gate terminal welded to p region J1 J2 J3 n Threaded stud P N P N J1 J2 J3 K G1 G2 or

9. The thyristor P N P N J1 J2 J3 A K A P N P N J1 J2 J3 K G1 G2 or Anode (Aluminum) Cathode P n P Gate terminal welded to p region J1 J2 J3 n Threaded stud

10. V AK I AK IHIH V Bo -V Bo

11. VB0>VB1>VB2 IG0 ˂ IG1 ˂ IG2 I AK > I H ( SCR v- i curve ) V AK I AK IHIH V Bo -V Bo V B1 V B2 V B0 :-Break down voltage. I H :- Holding current. I G0, 1, 2 :- the current on the thyristor Gat

12. Thyristor family Equivalent circuitCharacteristicSymbolname A K 1-silicon unilateral switch (SUS) A G K 2-silicon controlled switch (SCS) 3- Diac

13. Equivalent circuitCharacteristicSymbolname Two SCR”s in inverse parallel 4- triac Two SUS”s in inverse parallel 5- silicon bilateral switch(SBS) 6- gate turn off SCR(GTO)

14. بعض اشكال للثايرستور

17. The principle of thyristor operation can be explain with the use of its two –transistor model. From this figure, two – transistor model is obtain by bisection the two middle layers, along the dotted line Q1Q1 Q2Q2 J1J1 J2J2 J3J3 A K G P P P n nn J1J1 J2J2 G n P P n J3J3 J2J2 A K