Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 8: Problem 16

Sketch the ac equivalent model for a JFET if \(I_{D S S}=10 \mathrm{~mA}, V_{P}=-4 \mathrm{~V}, V_{G S_{Q}}=-2 \mathrm{~V}\), and \(g_{o s}=25 \mu \mathrm{S} .\)

Short Answer

Expert verified
The values in the AC equivalent model for the JFET are: \(R_{DS} = 40 k\Omega\) and controlled source, \(g_m = 5 mS\). The gate (G) terminal should be grounded for AC analysis.

Step by step solution

01

Calculate Drain-Source Resistance

The drain-source resistance (\(R_{DS}\)) can be found from the equation \(R_{DS} = 1/g_{os}\), where \(g_{os}=25 \mu S\). So, \(R_{DS} = 1/(25 \mu S) = 40 k\Omega\)
02

Calculate Transconductance

The transconductance (\(g_m\)) can be calculated using the formula \(g_m = -2 * I_{DSS} / V_P\), where \(I_{DSS}=10 mA\) and \(V_P=-4 V\). Therefore, \(g_m = -2 * 10 mA / -4 V = 5 mS\)
03

Create AC Equivalent Circuit Model

Now, with the calculated parameters, construct the JFET AC equivalent model. The \(g_m V_{GS}\) is the controlled source with the value of \(g_m\) calculated, and the \(R_{DS}\) resistance is set in parallel with the controlled source. Also, gate (G) terminal should be grounded for AC analysis.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A JFET \(\left(I_{D S S}=10 \mathrm{~mA}, V_{P}=-5 \mathrm{~V}\right)\) is biased at \(I_{D}=I_{D S S} / 4\). What is the value of \(g_{m}\) at that bias point?

If a JFET having a specified value of \(r_{d}=100 \mathrm{k} \Omega\) has an ideal voltage gain of \(A_{v}(\mathrm{FET})=-200\), what is the value of \(g_{m}\) ?

Sketch the ac equivalent model for a JFET if \(g_{f s}=5.6 \mathrm{mS}\) and \(g_{a s}=15 \mu \mathrm{S}\).

Calculate \(g_{m 0}\) for a JFET having device parameters \(I_{D S S}=12 \mathrm{~mA}\) and \(V_{P}=-4 \mathrm{~V}\).

For a JFET having device parameters \(g_{m 0}=5 \mathrm{mS}\) and \(V_{P}=-4 \mathrm{~V}\), what is the device current at \(V_{G S}=0 \mathrm{~V} ?\)
See all solutions

Recommended explanations on Physics Textbooks

Thermodynamics

Read Explanation

Fields in Physics

Read Explanation

Physics of Motion

Read Explanation

Medical Physics

Read Explanation

Astrophysics

Read Explanation

Magnetism

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free