Q 12-14-116JEE MainJEE Main 2022 (25 Jul, Shift 2)Medium
Two ideal diodes are connected in the network as shown in figure. The equivalent resistance between $A$ and $B$ is ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 25
With $A$ positive, the upper-left diode conducts (from $A$ towards the top node) and the upper-right diode is reverse biased (it only conducts from $B$'s side towards the top), so it is an open circuit.
From $A$ to the bottom node: the lower-left $20\ \Omega$ in parallel with the path through the top node and the vertical $20\ \Omega$: $20\parallel20 = 10\ \Omega$.
Then the $15\ \Omega$ to $B$: $R_{AB} = 10 + 15 = 25\ \Omega$.
Solution by Sreeraj P, M.Sc Physics