Bipolar Junction Transistors (BJT) — A/L Physics

How do I practise Bipolar Junction Transistors (BJT)?

1 question with a worked solution

1. In a common-emitter (CE) bipolar junction transistor (BJT) amplifier circuit, a small change in base current ΔI_B = 20 μA produces a corresponding change in collector current ΔI_C = 2.0 mA. What is the common-emitter forward current gain (β)?
   1. A) 50
   2. B) 200
   3. C) 100
   4. D) 0.99
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   Correct answer: C) 100

   The common-emitter current gain β (also denoted h_fe) is defined as the ratio of change in collector current to change in base current: β = ΔI_C / ΔI_B. Substituting: β = (2.0 × 10⁻³ A) / (20 × 10⁻⁶ A) = 2.0 × 10⁻³ / 0.020 × 10⁻³ = 100.

   Show worked solution

   Step 1: Formula: β = ΔI_C / ΔI_B. Step 2: β = 2.0 mA / 20 μA = 2000 μA / 20 μA = 100. Answer: 100.
   Modelled on: the A/L Physics examination pattern

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Next in the syllabus

Where does Bipolar Junction Transistors (BJT) fit in the syllabus?

Unit 9.4 · Year 2 · Term 2