DC Load Line and Operating Point

>>  For Common Emitter configuration, output characteristic are :

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>>  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.

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\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   ]

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>>  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

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Case 2 : Operating point near cutoff region 

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

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

 

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