In a forward-biased diode, what is the impedance?

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Multiple Choice

In a forward-biased diode, what is the impedance?

Explanation:
When a diode is forward biased, the depletion region narrows and carriers can cross the junction easily, so a current flows readily. Impedance here means how much voltage you need to push a given amount of current, i.e., dV/dI. Because the current rises rapidly with even a small increase in voltage in the forward region, the incremental (dynamic) resistance is small. In other words, the diode behaves like a low-resistance path once it’s conducting, aside from the typical forward voltage drop of about 0.6–0.7 V for silicon. So the impedance in forward bias is very low, not zero current and not infinite.

When a diode is forward biased, the depletion region narrows and carriers can cross the junction easily, so a current flows readily. Impedance here means how much voltage you need to push a given amount of current, i.e., dV/dI. Because the current rises rapidly with even a small increase in voltage in the forward region, the incremental (dynamic) resistance is small. In other words, the diode behaves like a low-resistance path once it’s conducting, aside from the typical forward voltage drop of about 0.6–0.7 V for silicon. So the impedance in forward bias is very low, not zero current and not infinite.

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