Question

Draw a plot of transfer characteristic (V_o vs Y_i) and show which portion of the characteristic is used in amplification and why ?

Draw the circuit diagram of base bias transistor amplifier in CE configuration and briefly explain its working.

Answer 1

The transfer characteristic has the form shown

The Active region of the transfer characteristic is used for amplification because in this region, I_C. increases almost linearly with increase of V_i; The circuit diagram of the base biased transistor amplifier, in CE configuration, is shown below

Working : The sinusoidal voltage, superimposed on the d.c. base bias, causes the base current to have sinusoidal variations.

As a result the collector current, also has similar sinusoidal variations present in it. The output, between the collector and the ground, is an amplified version of the input sinusoidal voltage.

(Also accept 'other forms' for explanation of 'working)