Load line & q point

2. Diode load line. The curve shows the diode response (I vs
VD) while the straight line shows the behavior of the linear
part of the circuit: I=(VDD-VD)/R. The point of intersection
gives the actual current and voltage.

6. The DC load represents the desirable combinations
of the collector current and the collector-emitter
voltage. It is drawn when no signal is given to the
input, and the transistor becomes bias.

8. the AC Load line on the Q point, and preferably use the
middle of the AC LL as the Q point.