Question

. For a common emitter amplifier, the audio voltageacross the collector resistance is 1 kΩ and the voltage developed is 3V.Ifcurrent amplification factor is 50, find the input signal voltage and basecurrent if the base resistance is 10kΩ.

Answer 1

collector current =  i_c = 3 V / 1 kohm = 3 milli Amp
given β = 50

current amplification factor = β
     β   = collector current i_c / base current i_b 
     β   =  3 m A / i_b

i_b = base current = 3 m A / 50 = 60 μA

base voltage = base resistance * base current = 60 μA * 10 kΩ
           = 0.6 Volts