JFET Dynamic Drain Resistance Calculation
The relationship between a JFET's amplification factor ($\mu$), transconductance ($g_m$), and dynamic drain resistance ($r_d$) is given by the formula:
$ r_d = \frac{\mu}{g_m} $
Applying the Formula
Given values:
- Amplification factor ($\mu$) = 80
- Transconductance ($g_m$) = $200 \text{ } \mu\text{S} = 200 \times 10^{-6} \text{ S}$
Calculating Dynamic Drain Resistance
Substitute the given values into the formula:
$ r_d = \frac{80}{200 \times 10^{-6} \text{ S}} $
$ r_d = \frac{80}{0.0002} \text{ } \Omega $
$ r_d = 400000 \text{ } \Omega $
Convert the result to kilo-ohms ($k\Omega$):
$ r_d = 400 \times 10^3 \text{ } \Omega = 400 \text{ k} \Omega $
Conclusion
The dynamic drain resistance ($r_d$) of the JFET is $400 \text{ k} \Omega$. This matches Option 3.
Important Questions from Field Effect Transistors
FET is like a switched on condition when it operates in ______ mode.
Which of the following is the characteristic of Field-effect transistor?
When VDS is the drain voltage and VDS(max) is the maximum drain voltage, the JFET will breakdown if:
Which of the following is true about the transconductance of a MOSFET in saturation (I Dis the Drain Current)?
Transconductance in an FET indicates how effectively the input voltage controls the
