In a circuit shown below, the collector current at Q-point is:

Concept:

Q-point is an abbreviation of quiescent point, it’s the point where the transistor is currently operating at. i.e the current values of V_ce and I_c on the I-V characteristics graph of BJT.(also applies for MOSFETs).

Q-point is controlled by a load line on the I-V graph, Load line is a line that connects the maximum Ic and Vce the transistor can handle for a certain circuit. (On the same graph), Q-point must be anywhere on that line.

Analysis:

For DC analysis open circuit of the capacitors.

Then;

Base current:

\(I_{B} = \frac{V_{CC}-V_{BE}}{R_{B}}\)

Collector current:

\(I_{C}=\beta I_{B} = \beta.\frac{V_{CC}-V_{BE}}{R_{B}}\)