DC Load Line and Operating Point

>>  For Common Emitter configuration, output characteristic are :

>>  DC Load line is plotted on output characteristic, graphically to calculate the DC values of $\displaystyle V_{CE}$ and $\displaystyle I_C$

>>  DC Load line obtained through KVL in output loop.

$\displaystyle V_{CC} - I_{C} R_{C} - V_{CE} = 0$

$\displaystyle I_{C} = - \frac {V_{CE}}{R_{C}} + \frac {V_{CC}}{R_C}$

>>  For a given value of Base current, the point of intersection of output characteristic and DC load line is called an operating point or Quiescent point.

>>  Operating point gives the DC values of $I_C$ and $V_{CE}$. [ This method is applied in industry to calculate the accurate value of $V_{CE}$ and $I_C$ ]

>>  For a given value of $R_C$ and $V_{CC}$. Thus it represents all collector current levels and corresponding collector-emitter voltages that can exist in the circuit.

SELECTION OF OPERATING POINT

Case 1 : Operating point near Saturation region

Case 2 : Operating point near cutoff region

Case 3 : Operating point at the center of Load line / Active region

>>  Output signal is perfect sinusoidal means no distortions are present in the output.