Explain the effect of Q point variation in case of CE amplifier
Answers
hey mate!
Q-point is an acronym for quiescent point. Q-point is the operating point of the transistor (ICQ,VCEQ) at which it is biased. The concept of Q-point is used when transistor act as an amplifying device and hence is operated in active region of input output characteristics. To operate the BJT at a point it is necessary to provide voltages and currents through external sources.
Importance of q point in transistor
Normally whatever signals we want to amplify will be of the order milli volts or less. If we directly input these signals to the amplifier they will not get amplified as transistor needs voltages greater than cut in voltages for it to be in active region. Only in active region of operation transistor acts as amplifier. So we can establish appropriate DC voltages and currents through BJT by external sources so that BJT operates in active region and superimpose the AC signals to be amplified.The DC voltage and current are so chosen that the transistor remains in active region for entire AC signal excursion. All the input AC signals variations happen around Q-point.