In biasing voltage Vcc and Vbb & resistance Rb and Rc are used such that the bjt biased in active region. There are three objective of biasing. To setup Ic and Vce. The BJT can set into active region by setting up the proper value of Ic and Vce.

Input Characteristics:

The DC load line can be varied by changing Vce and Rc where as output characteristics can be varied by changing Vbb and Rb. The point where DC load line meets output characteristics is called Q point quiscent point or operating point. The values corresponding to Q point are set up in the circuit. Q should be lines at the center of Q point.