question_answer

Draw the transfer characteristic curve of a base biased transistor in CE configuration. Explain clearly how the active region of the \[{{V}_{0}}\] versus \[{{V}_{i}}\], curve in a transistor is used as an amplifier.      

Answer:

                                        Using transistor as an amplifier. The slope of the linear part of the active region of the \[{{V}_{0}}\] versus \[{{V}_{i}}\] curve gives the rate of change of output with the input. If \[\Delta {{V}_{0}}\] and \[\Delta {{V}_{i}}\]. are the small changes in the output and input voltages, then \[\Delta {{V}_{0}}/\Delta {{V}_{i}}\] will be the small signal voltage gain \[{{A}_{V}}\] of the amplifier. If the forward \[{{V}_{BB}}\] is fixed at the midpoint of the active region, then the base biased CE transistor will behave as an amplifier with voltage gain \[\Delta {{V}_{0}}/\Delta {{V}_{i}}\]. Thus the linear portion of the active region of the transistor can be exploited for the use in amplifiers.