09W-quiz-2-sol

# 09W-quiz-2-sol - ECE65(Winter 2009 Midterm 2 Name Notes 1...

This preview shows pages 1–3. Sign up to view the full content.

ECE65 (Winter 2009), Midterm 2 Name: Notes: 1. Write your answers on these three sheets. 2. For each problem, 20% of points are alloacted for the correct final answer. Problem 1. Find the state of this transistor if v GS > v t . (5pts) By KVL: v DS = v GS . Since v GS > v t , the NMOS is ON (should be either in active or ohmic). Furthermore, since v DS = v GS > v GS - v t , NMOS should be in active region.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Problem 2. In the circuit below with Si diodes, find i for - 20 v s 20 V (13pts) S V - + i i S i D 5k 5k D1 D2 KCL: i D 1 = i D 2 = i D KCL: i s = i D + i KVL: v s = 5 × 10 3 i s + v D 1 + v D 2 KVL: v D 1 + v D 2 = 5 × 10 3 i Because the two didoes are in series, i D 1 = i D 2 = i D , the two diodes are either ON ( i D > = 0) or OFF ( i D = 0). For BOTH diodes being ON: v D 1 = v D 2 = v γ = 0 . 7 V, i D > 0. Substituting in the circuit equations we get: v s = 5 × 10 3 i s + v D 1 + v D 2 v s = 5 × 10 3 i s + 1 . 4 i s = 2 × 10 - 4 ( v s - 1 . 4) v D 1 + v D 2 = 5 × 10 3 i 1 . 4 = 5 × 10 3 i i = 0 . 28 mA i s = i D + i i D = i s - 0 . 28 × 10 - 3 = 2 × 10 - 4 ( v s - 1 . 4) - 2 . 8 × 10 - 4 i D > 0 2 × 10 - 4 ( v s - 1 . 4) - 2 . 8 × 10 - 4 > 0 v
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern