For CE transistor amplifier, the audio signal voltage across the collector resistance of 2 k is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is 1 k , then the input signal voltage is
- 10 mV
- 20 mV
- 30 mV
- 15 mV
Answer
(2) 20 mV
Solution
Collector current: iC = VoRC = 42 103 = 2 10-3 A
Base current: iB = iC = 2 10-3100 = 2 10-5 A
Input signal voltage: Vi = iB RB = 2 10-5 1 103
= 2 10-2 V = 20 mV
Answer: (2)