Concept:Once a silicon diode enters forward conduction beyond its knee voltage, its exponential \( I\text{-}V \) characteristic keeps the forward voltage drop clamped near its barrier potential.
Formula:$$V_F \approx V_B \approx 0.7\text{ V (for Silicon)}$$
Solution:- Beyond the threshold knee voltage (\( \approx 0.7\text{ V} \)), the diode's dynamic resistance becomes very small.
- Consequently, large increases in current produce only negligible increases in forward voltage drop, keeping it clamped near \( 0.7\text{ V} \).
Why other options are incorrect:- Option A: \( 0.0\text{ V} \) applies only to an idealized theoretical diode.
- Option B: \( 0.3\text{ V} \) is the forward voltage drop of a conducting germanium diode.
- Option C: \( 12.0\text{ V} \) would destroy a standard semiconductor diode through extreme thermal dissipation.
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