Page 1 1 Lecture 11, Slide 1 EECS40, Fall 2003 Prof. King Lecture #11 ANNOUNCEMENTS • Homework Assignment #4 will be posted today • Midterm #1: Monday Sept. 29 th (11:10AM-12:00PM) – closed book; one page (8.5”x11”) of notes & calculator allowed – covers Chapters 1-5 in textbook (HW#1-4) • Midterm Review Session: Friday 9/26 7-9PM, 277 Cory • Extra office hours: – Steve: 9/26 from 12-2PM – Farhana: 9/27 from 1-3PM, 9/28 from 9-11AM • Practice problems and old exam are posted online OUTLINE – Review: op amp circuit analysis – The capacitor (Chapter 6.2 in text) Lecture 11, Slide 2 EECS40, Fall 2003 Prof. King Review: Op Amp Circuit Analysis Procedure: 1. Assume that the op amp is ideal a) Apply KCL at (+) and (–) terminals, noting i p = 0 & i n = 0 b) Note that v n = v p c) Write an expression for v o 2. Calculate v o 3. Check: Is the op-amp operating in its linear region? If V – = v o = V + , , then the assumption is valid. If calculated v o > V + , then v o is saturated at V + If calculated v o < V – , then v o is saturated at V – + – + v n – + v p – i p i n i o + v o – + – + v n – + v p – i p i n i o + v o – Page 2 1 Lecture 11, Slide 1 EECS40, Fall 2003 Prof. King Lecture #11 ANNOUNCEMENTS • Homework Assignment #4 will be posted today • Midterm #1: Monday Sept. 29 th (11:10AM-12:00PM) – closed book; one page (8.5”x11”) of notes & calculator allowed – covers Chapters 1-5 in textbook (HW#1-4) • Midterm Review Session: Friday 9/26 7-9PM, 277 Cory • Extra office hours: – Steve: 9/26 from 12-2PM – Farhana: 9/27 from 1-3PM, 9/28 from 9-11AM • Practice problems and old exam are posted online OUTLINE – Review: op amp circuit analysis – The capacitor (Chapter 6.2 in text) Lecture 11, Slide 2 EECS40, Fall 2003 Prof. King Review: Op Amp Circuit Analysis Procedure: 1. Assume that the op amp is ideal a) Apply KCL at (+) and (–) terminals, noting i p = 0 & i n = 0 b) Note that v n = v p c) Write an expression for v o 2. Calculate v o 3. Check: Is the op-amp operating in its linear region? If V – = v o = V + , , then the assumption is valid. If calculated v o > V + , then v o is saturated at V + If calculated v o < V – , then v o is saturated at V – + – + v n – + v p – i p i n i o + v o – + – + v n – + v p – i p i n i o + v o – 2 Lecture 11, Slide 3 EECS40, Fall 2003 Prof. King Op Amp Circuit Analysis Example Consider the following circuit: Assume the op amp is ideal. a) Calculate v o if v s = 100 mV b) What is the voltage gain v o /v s of this amplifier? c) Specify the range of values of v s for which the op amp operates in a linear mode + – + v o – – + v s i n + v p – + v n – 10 k? 1 k? 10 V –10 V Lecture 11, Slide 4 EECS40, Fall 2003 Prof. King Op Amp Circuit Analysis Example cont’d. What if the op amp is not ideal? R i = 10 k? R o = 1 k? A = 10 3 – + v s 10 k? 1 k? + v o – + – R o A(v p –v n ) R i + v p – + v n – Page 3 1 Lecture 11, Slide 1 EECS40, Fall 2003 Prof. King Lecture #11 ANNOUNCEMENTS • Homework Assignment #4 will be posted today • Midterm #1: Monday Sept. 29 th (11:10AM-12:00PM) – closed book; one page (8.5”x11”) of notes & calculator allowed – covers Chapters 1-5 in textbook (HW#1-4) • Midterm Review Session: Friday 9/26 7-9PM, 277 Cory • Extra office hours: – Steve: 9/26 from 12-2PM – Farhana: 9/27 from 1-3PM, 9/28 from 9-11AM • Practice problems and old exam are posted online OUTLINE – Review: op amp circuit analysis – The capacitor (Chapter 6.2 in text) Lecture 11, Slide 2 EECS40, Fall 2003 Prof. King Review: Op Amp Circuit Analysis Procedure: 1. Assume that the op amp is ideal a) Apply KCL at (+) and (–) terminals, noting i p = 0 & i n = 0 b) Note that v n = v p c) Write an expression for v o 2. Calculate v o 3. Check: Is the op-amp operating in its linear region? If V – = v o = V + , , then the assumption is valid. If calculated v o > V + , then v o is saturated at V + If calculated v o < V – , then v o is saturated at V – + – + v n – + v p – i p i n i o + v o – + – + v n – + v p – i p i n i o + v o – 2 Lecture 11, Slide 3 EECS40, Fall 2003 Prof. King Op Amp Circuit Analysis Example Consider the following circuit: Assume the op amp is ideal. a) Calculate v o if v s = 100 mV b) What is the voltage gain v o /v s of this amplifier? c) Specify the range of values of v s for which the op amp operates in a linear mode + – + v o – – + v s i n + v p – + v n – 10 k? 1 k? 10 V –10 V Lecture 11, Slide 4 EECS40, Fall 2003 Prof. King Op Amp Circuit Analysis Example cont’d. What if the op amp is not ideal? R i = 10 k? R o = 1 k? A = 10 3 – + v s 10 k? 1 k? + v o – + – R o A(v p –v n ) R i + v p – + v n – 3 Lecture 11, Slide 5 EECS40, Fall 2003 Prof. King Re-draw the circuit & analyze: KCL @ node a: KCL @ node b: – + v s 1 k? + v n – + – 10 3 (–v n ) 1 k? 10 k? 10 k? + v o – 10 87 . 9 < ? - s o v v ab Lecture 11, Slide 6 EECS40, Fall 2003 Prof. King Effect of Load Resistance R L KCL @ node b: • For an ideal op amp (R o = 0 ? ), v o does not depend on the “load”. However, for a realistic op amp, it does. – + v s 1 k? + v n – + – 10 3 (–v n ) 1 k? 10 k? 10 k? + v o – 87 . 9 75 . 9 < ? - s o v v ab R L =1 k?Read More

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