Answer: I Cn /I E.
- A I<sub>Cn</sub>/I<sub>E</sub>
- B I<sub>Cp</sub>/I<sub>E</sub>
- C I<sub>E</sub>/I<sub>C</sub>
- D I<sub>B</sub>/I<sub>C</sub>
Correct answer: A. I<sub>Cn</sub>/I<sub>E</sub>
Explanation: Emitter injection efficiency gamma = fraction of emitter current that is due to minority carriers injected into base. gamma = I<sub>En</sub>/I<sub>E</sub> for npn.
Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.
Concept context
Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.