Stability of Operating Point

Consider the three operating points of transistor operating in the common emitter amplifier. 

1.   Near cut off region

2.   Near saturation region

3.   In the middle of active region

If operating point is selected near cutoff region, the output is clipped in the negative half cycle as shown in the figure 1.

Figure 1

If operating point is selected near the saturation region, then output is clipped in positive cycle as shown in the figure 2.

                                      Fig. 2                                                                 Fig. 3

If operating point is selected in middle of the active region, then there is no clipping and the output follows input as shown in the figure 3. If the input is large then clipping at both sides will take place. First circuit for biasing the transistor is CE configuration is fixed bias.

In the biasing circuit shown in the figure 4(a), 2 different power supplies are needed. To avoid the use of 2 supplies the base resistance RB is connected to V_CC as shown in the figure 4(b).

                  Figure 4(a)                                                                Figure 4(b)

V_CC is still the forward biasing emitter diode. In this circuit Q point is quite unstable. The base resistance R_B can be selected by noting the needed base current IB for the operating point Q.

I_B = (V_CC - V_BE ) / R_B

Voltage across base emitter junction is nearly 0.7 V. As V_CC is usually quite high i.e. I_B = V_CC/ R_B

As I_B is constant therefore it is called as fixed bias circuit.

Email based Electronics Devices and circuits assignment help - homework help at Expertsmind

Are you searching Electronics Engineering assignment help expert for help with Stability of Operating Point questions?  Stability of Operating Point topic is not easier to learn without any external help?  We at www.expertsmind.com offers free lecture notes for Electronics Devices and circuits assignment help and Electronics Devices and circuits homework help. Live tutors are available 24x7 hours for helping students in their Stability of Operating Point related problems. We provide step by step Stability of Operating Point question's answers with 100% plagiarism free content. We prepare quality content and notes for Stability of Operating Point topic under Electronics Devices and circuits theory and study material. These are avail for subscribed users and they can get advantages anytime.

Why Expertsmind for assignment help

1. Higher degree holder and experienced experts network
2. Punctuality and responsibility of work
3. Quality solution with 100% plagiarism free answers
4. Time on Delivery
5. Privacy of information and details
6. Excellence in solving electronics engineering questions in excels and word format.
7. Best tutoring assistance 24x7 hours