NTA Abhyas JEE Main2020PhysicsSemiconductorsPractice
For common emitter transistor amplifier, the audio signal voltage across the collector resistance of 2 k Ω is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is 1 k Ω then the input signal voltage is
Options
- A10     mV
- B20 mV
- C30     mV
- D15     mV
Correct answer
B. 20 mV
Step-by-step solution
R C = 2   k Ω       V 0 = 4   V I C = V 0 R c = 4   V 2   k Ω = 2   m A β = I C I B = 100 ⇒ I B = I C 100 = 2 × 10 - 5   A V i n = I B R i = 2 × 10 - 5 × 1   k Ω = 20   m V