For a CE-transistor amplifier, the audio signal voltage across the collected resistance of 2 kΩ is 2 V. Suppose the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is 1 kΩ.
Collector resistance, R C = 2 kΩ = 2000 Ω
Audio signal voltage across the collector resistance, V = 2 V
Current amplification factor of the transistor, β = 100
Base resistance, R B = 1 kΩ = 1000 Ω
Input signal voltage = V i
Base current = I B
We have the amplification relation as: V/Vi = β Rc/Rb
Voltage amplification, Vi = V Rb / β Rc
= 2x1000 / 100x2000 = 0.01 V
Therefore, the input signal voltage of the amplifier is 0.01 V.
Base resistance is given by the relation: RB = Vi / IB
= 0.01 / 1000 = 10 μA
Therefore, the base current of the amplifier is 10 μA.
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