Biasing the FET:

FET can also be biased as an amplifier. By taking the common source drain characteristic of a JFET. For the linear amplification, Q point should be selected somewhere in saturation region. Q point is selected on basis of the AC performance that is gain, noise, power, frequency response, current and voltage ratings.

Gate Bias:

Figure1, shows the circuit of simple gate bias.

Figure 1

The separate V_GS supply is taken in use to set up Q point. This is the worst method to select Q point. The reason is that there is significant variation in between the maximum and minimum values of FET parameters for example

                    IDSS            VGS(off)

Minimum         4mA                -2V

Maximum        13mA               -8V

This shows that the minimum and maximum transductance curves are displaced as shown in the figure 2.

Gate bias applies the fixed voltage to the gate. The fixed voltage results in the Q point which is highly sensitive to the particular JFET used. For example, if V_GS= -1V the Q point may vary from Q₁  to Q₂  depending upon the JFET parameter is use.

At Q₁, I_D= 0.016 (1 - (1/8))2 = 12.3 mA At Q₂, I_D= 0.004 (1-(1/2))2 = 1 mA.

The variation in the drain current is very large.

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

Are you searching Electronics Engineering assignment help expert for help with Gate Bias questions?  Gate Bias 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 Gate Bias related problems. We provide step by step Gate Bias question's answers with 100% plagiarism free content. We prepare quality content and notes for Gate Bias 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