[figure] In the circuit shown here, assuming threshold voltage of diode is negligibly small, then voltage VAB is correctly represented by:
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- VAB would be zero at all times.
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Answer
(2) [figure]
Solution
The diode conducts only when the lower terminal of the source is at the higher potential (current: lower terminal → diode → B → R → A → upper terminal).
When V = V0 t > 0 (upper terminal positive), the diode is reverse biased no current through R VAB = 0.
When V0 t < 0, the ideal diode conducts B is joined to the lower terminal and A to the upper terminal
VAB = V0 t (negative).
VAB is zero in the positive half cycles and follows the negative half cycles of the input, as in option (2).
Answer: (2)