. In the following circuits PN-junction diodes

D1, D2 and D3 are ideal for the following potentials of A and B. The correct increasing order of resistance between Aand B will be 


A. (i) < (ii) < (iii)

B. (iii) < (ii) < (i)

C. (ii) = (iii) < (i)

D. (i) = (iii) < (ii)

Best Answer

Ans: C

Sol: (i) VA = – 10V and VB = – 5V 

Diodes D1 and D3 are reverse biased and D2 is forward biased 


(ii) When VA = – 5V and VB = – 10V Diodes D2 is reverse biased D1 and D2 are forward biased 


(iii) In this case equivalent resistance between A and B is also R. 

Hence (ii) = (iii) < (i)



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