Diode I-v Characteristic
Mediumphysics
In forward region, diode current increases roughly?
Select the correct option:
Solution
Incorrect! Answer:
Exponentially with voltage
- Shockley Diode Equation: The current I through an ideal PN junction is given by I=Is(eV/ηVT−1).
- Variables:
- V: Applied forward voltage.
- Is: Reverse saturation current.
- VT: Thermal voltage (≈26 mV at RT).
- Forward Bias Behavior: When V is positive and greater than a few VT, the exponential term dominates (eV/ηVT≫1).
- Result: The current follows an exponential growth pattern with respect to the applied voltage after crossing the 'knee' or 'cut-in' voltage.
- Linear Check: Resistors follow Ohm's Law (linear); diodes are non-ohmic.
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About This Question
- Subject
- physics
- Chapter
- semiconductor devices
- Topic
- diode i-v characteristic
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Exponentially with voltage
- Shockley Diode Equation: The current I through an ideal PN junction is given by I=Is(eV/ηVT−1).
- Variables:
- V: Applied forward voltage.
- Is: Reverse saturation current.
- VT: Thermal voltage (≈26 mV at RT).
- Forward Bias Behavior: When V is positive and greater than a few VT, the exponential term dominates (eV/ηVT≫1).
- Result: The current follows an exponential growth pattern with respect to the applied voltage after crossing the 'knee' or 'cut-in' voltage.
- Linear Check: Resistors follow Ohm's Law (linear); diodes are non-ohmic.
This medium difficulty physics question is from the chapter semiconductor devices, covering the topic of diode i-v characteristic. It appeared in the 2025 exam.
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