In the figure, assuming the diodes to be ideal:- |
$D_2$ is forward biased and $D_1$ is reverse biased and hence no current flows from B to A and vice-versa $D_1$ is forward biased and $D_2$ is reverse biased and hence current flows from A to B $D_1$ and $D_2$ are both forward biased and hence current flows from A to B $D_1$ and $D_2$ are both reverse biased and hence no current flows from A to B and vice-versa |
$D_2$ is forward biased and $D_1$ is reverse biased and hence no current flows from B to A and vice-versa |
The correct answer is Option (1) → $D_2$ is forward biased and $D_1$ is reverse biased and hence no current flows from B to A and vice-versa Node at left (A) is tied to −15 V source (through R, so anode of D1 ≈ −15 V). Bottom node B = 0 V (ground). D1 orientation: anode at left node, cathode at the vertical node to the right. D2 orientation: anode at bottom (B = 0 V), cathode at the vertical node. Since the left supply is −15 V, the vertical node will be at a negative potential (less than 0 V). Hence $V_{B} - V_{\text{vertical}} \geq 0.7\ \text{V} \;\;\Rightarrow\;\;$ D2 is forward biased. $V_{\text{anode(D1)}} - V_{\text{cathode(D1)}} \lt 0\ \text{V} \;\;\Rightarrow\;\;$ D1 is reverse biased. Therefore, D2 conducts and D1 is off; no continuous current path exists between A and B through both diodes. Correct option: D2 forward biased and D1 reverse biased; hence no current flows from B to A and vice-versa. |