Q. In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. If the base resistance is 1 kΩ and the current amplification of the transistor is 100, the input signal voltage is
A) 10 mV
B) 0.1 V
C) 1.0 V
D) 1 mV
Explanation
[Solution from source] Voltage gain of a CE amplifier = β(R_C/R_B) = 100 × (2 kΩ/1 kΩ) = 200. Input voltage = output/gain = 2 V/200 = 0.01 V = 10 mV. Taking 0.1 V comes from using only the resistance ratio or only β instead of their product. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.