For a CE transistor amplifier, the audio signal voltage across the collector resistance of 2.0 k is 2.0 ~V . Suppose the current amplification factor of the transistor is 100 , What should be the value of R _ B in series with V _ BB supply of 2.0 ~V if the dc base current has to be 10 times the signal current?

Step-by-step solution

The output ac voltage is 2.0 ~V . So, the ac collector current i _ C =2.0 / 2000=1.0 ~mA . The signal current through the base is, therefore given by i _ B = i _ C / =1.0 ~mA / 100=0.010 ~mA The dc base current has to be 10 0.010=0.10 ~mA R _ B = ( V _ BB - V _ BE ) / I _ B Assuming V _ BE =0.6 ~V , R _ B =(2.0 .0 .6) / 0.10=14 k