In a transistor, the current gain β is defined as: MCQ with Answer and Explanation

In a transistor, the current gain β is defined as:
A. I_E / I_C
B. I_C / I_B
C. I_C / I_E
D. I_B / I_C
Answer: Option B
Solution (By JKSSB Mock Tests)
For a bipolar junction transistor (BJT) in common-emitter configuration, DC current gain β = I_C / I_B, where I_C is collector current, I_B base current. Typical β values range 20-200. Option D is α (common-base gain). Memory tip: 'β = collector current / base current; large β means small base current controls large collector current'. This definition-based question tests electronics fundamentals, frequently examined in competitive exams. Always distinguish β (CE configuration) from α (CB configuration) and their relationship: β = α/(1-α).

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