Download presentation

Presentation is loading. Please wait.

Published byBrandon Leaver Modified over 2 years ago

1
Circuits Lecture 7: Equivalence 李宏毅 Hung-yi Lee

2
Textbook Chapter 2.1, 2.3

3
Outline Concept of Equivalent networks Equivalent networks only with resistors Equivalent networks with independent sources Equivalent networks with controlled sources

4
Outline Concept of Equivalent networks Equivalent networks only with resistors Equivalent networks with independent sources Equivalent networks with controlled sources

5
Network Two-terminal network Network: Part of a complete circuit

6
Equivalent Network Network A and B are equivalent. Network A v i Network B v i i v i-v characteristics Equivalent networks in circuits are just like functions in programming!

7
Circuit Design is like Programming int main () { // create array of grades double quiz1_grade[50] = …… double total = 0; for (int i=0; i<50; i++){ total += quiz1_grade[i]; } double avg = total / 50; print avg; return 0; } (the program for computing the average score of the first quiz) The complete circuit is the “main”. Put everything in “main” is not a good idea.

8
Circuit Design is like Programming Use function int main () { // create array of grades double quiz1_grade[50] = …… print avg_score(quiz1_grade); } function avg_score(double* score){ double total = 0; for (int i=0; i<50; i++){ total += score[i]; } return total/50; } Define IO of a function: input: double array (scores) output: double (average score) Easy to read! Can be re-used! Understandable name We do not care what happens in the function.

9
Circuit Design is like Programming Complete Circuit (Main) i v (IO of function) Name??? Network (function) Simpler equivalent network (function name) Function i-v characteristics

10
Benefit of Equivalent Network 1. Simplify the complete circuit Easier to analyze 2. Useful network can be reused just like elements Voltage amplifier (refer to lecture 5) Current source (later) Negative Resistor (later)

11
Outline Concept of Equivalent networks Equivalent networks only with resistors Equivalent networks with sources Equivalent networks with controlled sources

12
Series i-v curse

13
Parallel i-v curse

14
Example 2.4 Find i

15
Beyond Series and Parallel = What is R eq ? R eq Find i-v characteristics Way1: Add voltage source find current Way2: Add current source find voltage

16
Cubic Puzzle All resistors have resistance R. A and B are the two terminals of the network. = What is R eq ? R eq Hint: consider i-v characteristics

17
Cubic Puzzle 2 (solution is at the end of the slides)

18
Infinity Puzzle = What is R eq ? R eq Infinite resistors (solution is at the end of the slides)

19
Outline Concept of Equivalent networks Equivalent networks only with resistors Equivalent networks with sources Equivalent networks with controlled sources

20
Sources i-v curse Voltage Sources Current Sources i-v curse

21
Source Transformation

22
The two circuits are equivalent. and

23
Source Transformation

25
Why Source Transformation? Parallel

26
Why Source Transformation? Series Be careful about the directions of voltage and current sources

27
Example Find v o Simply the networks by their equivalent networks

28
Example Find v o Network A Network B

29
Example Find v o Bad idea…… Do not put the target in the network to be simplified. How about ….

30
Example Find v o Two-terminal Network

31
Example Find equivalent network Typical Network

32
Example Find equivalent network

33
Example

34
Outline Concept of Equivalent networks Equivalent networks only with resistors Equivalent networks with sources Equivalent networks with controlled sources

35
Equivalent Network with Controlled Source – Example 2.8 What is the equivalent network? Find the i-v characteristics Resistor Negative Resistor!

36
Source Transformation for Controlled Sources vcvc icic

37
Equivalent Network with Controlled Source – Example 2.8

38
Remind 1 When computing i-v characteristics, we need reference direction of v and i Without reference direction, we cannot really answer the i-v characteristics Load Network Source Network The current goes into the terminal with high potential. The current goes out the terminal with high potential. Network without sources Network with sources

39
Remind 2 Select good networks Put a controlled source and its control variable in the same network

40
Three-terminal Network Chapter 4.6 (out of the scope) Three-terminal network

41
Four-terminal Network Chapter 14

42
Problem 2.32, 2.36

43
Thank you!

44
Beyond Series and Parallel = What is R eq ? R eq Find i-v characteristics: Way1: Add voltage source find current Way2: Add current source find voltage Ans:1.1K

45
Cubic Puzzle All resistors have resistance R. A and B are the two terminals of the network. = What is R eq ? R eq

46
Cubic Puzzle 2 http://e2e.ti.com/blogs_/archives/b/thesignal/archive/2013/03/18/resistor- puzzle-solution-and-a-rant-on-schematics.aspx?DCMP=scblog&HQS=hpa-pa- opamp-thehub-20140129-thesignal-20130318-en

47
Infinity Puzzle = What is R eq ? R eq Infinite resistors https://www.youtube.com/watch?v=MgN7h1z5bMQ (the answer in the video is not correct)

48
Problem - Answer

49
Brain Teaser http://rochester.ieee.org/files/2014/03/Newsletter_4-2014.pdf

50
Acknowledgement 感謝 范廷瀚 (b02) 糾正 Infinity Puzzle 的錯誤答案

Similar presentations

Presentation is loading. Please wait....

OK

Dr. Jie ZouPHY 13611 Chapter 28 Direct Current Circuits.

Dr. Jie ZouPHY 13611 Chapter 28 Direct Current Circuits.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on principles of object-oriented programming pdf Ppt on job evaluation forms What does appt only means of Ppt on chromosomes and chromatin difference Topics for ppt on environmental science Ppt on retail management information system Ppt on porter's five forces pdf Ppt on surface area and volume for class 9th Ppt on cross docking Ppt on management by objectives steps