(2)Forward-blocking state(正向阻断状态):When a forward (Vak>0) voltage is applied, the flowof current is blocked by the junctions J2AYP1S1(N)N11J2R20GJ3G(N+)13N2JK6K12
12 (2) Forward-blocking state (正向阻断状态): When a forward (vAK>0) voltage is applied, the flow of current is blocked by the junctions J2
(3) Turn on (开通):When a forward (vak>O) voltage is applied, and a pulse ofpositive voltage (Vgk) is applied to gate with respect to thecathode, the thyristor is in its on state. Once the devicebegins to conduct, it is latched on and the gate current canbe removed.AYP11J1(N)QiG→iB2↑→ic2↑→ic1 (iA)1N122OG13OG(N+)N2TK6K
13 (3) Turn on (开通): When a forward (vAK>0) voltage is applied, and a pulse of positive voltage (vGK) is applied to gate with respect to the cathode, the thyristor is in its on state. Once the device begins to conduct, it is latched on and the gate current can be removed. iG →iB2↑→iC2↑→iC1 (iA)↑ ↑————————↓
(4) Turn off (关断):Thethyristor cannot beturnedoffbythegateOnly when the anode current tries to go negative,does the thyristor turn off and the current go to zeroA?P1S1(N)QN1J2R20G13G(N+)J3N26K6K14
14 (4) Turn off (关断): The thyristor cannot be turned off by the gate. Only when the anode current tries to go negative, does the thyristor turn off and the current go to zero
3Staticcharacteristicsofthyristor（晶闸管的静态特性）forwardconductingIA·Blocking whenreverse biased, nomatter if there isincreasing lGgate current appliedIG=0IHVRSMVRRM·Conducting only0VVbowhenforwardVDRMAKreverseforwardVDSMbiased and there isblockingblockingtrigaeringcurrent(orcalled tfiringcurrent)（触发电流）avalancheapplied to the gatebreakdown
3 Static characteristics of thyristor (晶闸管的静态特性) O IA Vbo VAK VDSM VDRM VRSM VRRM forward conducting avalanche breakdown reverse blocking increasing IG forward blocking IH IG2 IG1 IG=0 •Blocking when reverse biased, no matter if there is gate current applied •Conducting only when forward biased and there is triggering current (or called firing current)(触发电流) applied to the gate
.Once triggered on,forward conductingAwill be latched onconducting evenwhen the gateincreasing lGcurrent is no longerIG=0IHVRSMVRRMapplied.0VVo?Turning off:VDRMAKreverseforwardVDSMblockingdecreasing currentblockingto be near zero withthe effect of externalpower circuit.avalanchebreakdown16
16 •Once triggered on, will be latched on conducting even when the gate current is no longer applied. •Turning off: decreasing current to be near zero with the effect of external power circuit. O IA Vbo VAK VDSM VDRM VRSM VRRM forward conducting avalanche breakdown reverse blocking increasing IG forward blocking IH IG2 IG1 IG=0