Draw a neat labelling V-I characteristics of SCR and explain the region

Draw a neat labelling V-I characteristics of SCR and explain the region
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2 Answers

Answer :

V-I characteristics of SCR:

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Operating regions: 1) Forward Blocking region: In this region, the SCR is forward biased but not triggered. It carries only forward leakage current. The SCR in this region is treated as OFF switch. 2) Forward conduction region: In this region, the SCR conducts the forward current and latched into conduction after triggering. The SCR in this region is treated as ON switch. 3) Reverse blocking region: In this region, the SCR is reverse biased, hence carries only reverse leakage current. The SCR in this region is treated as OFF switch. 4) Reverse conduction region: In this region, the SCR conducts the reverse current after the breakdown of reverse biased junctions. The SCR get damaged if operated in this region. 

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Answer :

(i) Latching current: It is the minimum anode current required to maintain the SCR in the conduction state just after turn-on and the gate signal has been removed. 

(ii) Holding current: It is the minimum anode current required to hold the conducting SCR in the ON state. 

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