1 / 35

EEL 3041 Sp 2012 Principles of Electrical Engineering

EEL 3041 Sp 2012 Principles of Electrical Engineering. Instructor: Dr. Harold Klee Office: Harris Center 206 Office Hours: tbd Telephone: (407) 823-2270 Email: harold.klee@ucf.edu Class Hours: M,W 12:00-13:15 Classroom: HEC 104

helga
Download Presentation

EEL 3041 Sp 2012 Principles of Electrical Engineering

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EEL 3041 Sp 2012Principles of Electrical Engineering • Instructor: Dr. Harold Klee • Office: Harris Center 206 • Office Hours: tbd • Telephone: (407) 823-2270 • Email: harold.klee@ucf.edu • Class Hours: M,W 12:00-13:15 • Classroom: HEC 104 • Textbook: A Brief Introduction to Circuit Analysis, J. D. Irwin, Wiley, 2003 • Course Website http://www.eecs.ucf.edu/courses/eel3041/spr2012

  2. Learning Objectives • Fundamental laws of electrical circuits and circuit analysis, fundamentals of electronics and power systems: • 1 Course • 2 Basic Variables: voltage and current • 3 Fundamental Laws: Ohm’s, KCL, KVL

  3. Topics/Chapters • Basic concepts of electrical engineering • Resistive circuit analysis • Transient circuit analysis • AC steady-state analysis • Steady state power analysis • Variable frequency network • Electronics fundamentals

  4. Unannounced quizzes will be given throughout the semester and will add to your exam scores and therefore affect your final grade. NO individual makeup opportunity will be given for any missing quiz. • Homework will be assigned on a weekly basis but will not be collected or graded. It is important that you do the homework. Some of the quiz questions will be similar or even identical to homework problems. A list of all home work problems is included in the syllabus. Exam 1 30% Exam 2 30% Final Exam (comprehensive) 40% Quizzes

  5. Grade System • A 90-100 • B 80-89 • C 70-79 • D 60-69 • F 0-59

  6. CIRCUITS 1 DEVELOP TOOLS FOR THE ANALYSIS AND DESIGN OF BASIC LINEAR ELECTRIC CIRCUITS

  7. A FEW WORDS ABOUT ANALYSIS USING MATHEMATICAL MODELS

  8. BASIC STRATEGY USED IN ANALYSIS

  9. FOR THE FIRST PART WE WILL BE EXPECTED TO SOLVE SYSTEMS OF ALGEBRAIC EQUATIONS LATER THE MODELS WILL BE DIFFERENTIAL EQUATIONS OF THE FORM THE MATHEMATICS CLASSES - LINEAR ALGEBRA, DIFFERENTIAL EQUATIONS- PROVIDE THE TOOLS TO SOLVE THE MATHEMATICAL MODELS MATHEMATICAL ANALYSIS DEVELOP A SET OF MATHEMATICAL EQUATIONS THAT REPRESENT THE CIRCUIT - A MATHEMATICAL MODEL - LEARN HOW TO SOLVE THE MODEL TO DETERMINE HOW THE CIRCUIT WILL BEHAVE IN A GIVEN SITUATION THIS COURSE TEACHES THE BASIC TECHNIQUES TO DEVELOP MATHEMATICAL MODELS FOR ELECTRIC CIRCUITS THE MODELS THAT WILL BE DEVELOPED HAVE NICE MATHEMATICAL PROPERTIES. IN PARTICULAR THEY WILL BE LINEAR WHICH MEANS THAT THEY SATISFY THE PRINCIPLE OF SUPERPOSITION

  10. TYPICAL LINEAR CIRCUIT LOW DISTORTION POWER AMPLIFIER ELECTRIC CIRCUIT IS AN INTERCONNECTION OF ELECTRICAL COMPONENTS

  11. BASIC CONCEPTS LEARNING GOALS • System of Units: The SI standard system; prefixes • Basic Quantities: Charge, current, voltage, power and energy • Circuit Elements: Active and Passive

  12. http://physics.nist.gov/cuu/index.html

  13. SI DERIVED BASIC ELECTRICAL UNITS

  14. ONE AMPERE OF CURRENT CARRIES ONE COULOMB OF CHARGE EVERY SECOND. VOLT IS A MEASURE OF ENERGY PER CHARGE. TWO POINTS HAVE A VOLTAGE DIFFERENCE OF ONE VOLT IF ONE COULOMB OF CHARGE GAINS (OR LOSES) ONE JOULE OF ENERGY WHEN IT IS MOVED FROM ONE POINT TO THE OTHER. OHM IS A MEASURE OF THE RESISTANCE TO THE FLOW OF CHARGE. THERE IS ONE OHM OF RESISTANCE BETWEEN TWO POINTS IF ONE VOLT OF ELECTROMOTIVE FORCE IS REQUIRED TO MOVE ONE AMPERE OF CURRENT BETWEEN THE TWO POINTS IT REQUIRES ONE WATT OF POWER TO MOVE ONE AMPERE OF CURRENT BETWEEN TWO POINTS WITH A VOLTAGE DIFFERENCE OF ONE VOLT

  15. CURRENT AND VOLTAGE RANGES

  16. Strictly speaking current is a basic quantity and charge is derived. However, physically the electric current is created by a movement of charged particles. What is the meaning of a negative value for q(t)? PROBLEM SOLVING TIP IF THE CHARGE IS GIVEN DETERMINE THE CURRENT BY DIFFERENTIATION IF THE CURRENT IS KNOWN DETERMINE THE CHARGE BY INTEGRATION A PHYSICAL ANALOGY THAT HELPS VISUALIZE ELECTRIC CURRENTS IS THAT OF WATER FLOW. CHARGES ARE VISUALIZED AS WATER PARTICLES

  17. EXAMPLE FIND THE CHARGE THAT PASSES DURING IN THE INTERVAL 0<t<1 Units? EXAMPLE FIND THE CHARGE AS A FUNCTION OF TIME And the units for the charge?...

  18. DETERMINE THE CURRENT Here we are given the charge flow as function of time. To determine current we must take derivatives. PAY ATTENTION TO UNITS

  19. THE DOUBLE INDEX NOTATION IF THE INITIAL AND TERMINAL NODE ARE LABELED ONE CAN INDICATE THEM AS SUBINDICES FOR THE CURRENT NAME A POSITIVE VALUE FOR THE CURRENT INDICATES FLOW IN THE DIRECTION OF THE ARROW (THE REFERENCE DIRECTION) A NEGATIVE VALUE FOR THE CURRENT INDICATES FLOW IN THE OPPOSITE DIRECTION THAN THE REFERENCE DIRECTION POSITIVE CHARGES FLOW RIGHT-LEFT POSITIVE CHARGES FLOW LEFT-RIGHT CONVENTION FOR CURRENTS IT IS ABSOLUTELY NECESSARY TO INDICATE THE DIRECTION OF MOVEMENT OF CHARGED PARTICLES. THE UNIVERSALLY ACCEPTED CONVENTION IN ELECTRICAL ENGINEERING IS THAT CURRENT IS FLOW OF POSITIVE CHARGES. AND WE INDICATE THE DIRECTION OF FLOW FOR POSITIVE CHARGES -THE REFERENCE DIRECTION-

  20. This example illustrates the various ways in which the current notation can be used

  21. IF THE CHARGE GAINS ENERGY MOVING FROM a TO b THEN b HAS HIGHER VOLTAGE THAN a. IF IT LOSES ENERGY THEN b HAS LOWER VOLTAGE THAN a DIMENSIONALLY VOLT IS A DERIVED UNIT CONVENTIONS FOR VOLTAGES ONE DEFINITION FOR VOLT TWO POINTS HAVE A VOLTAGE DIFFERENTIAL OF ONE VOLT IF ONE COULOMB OF CHARGE GAINS (OR LOSES) ONE JOULE OF ENERGY WHEN IT MOVES FROM ONE POINT TO THE OTHER VOLTAGE IS ALWAYS MEASURED IN A RELATIVE FORM AS THE VOLTAGE DIFFERENCE BETWEEN TWO POINTS IT IS ESSENTIAL THAT OUR NOTATION ALLOWS US TO DETERMINE WHICH POINT HAS THE HIGHER VOLTAGE

  22. THE + AND - SIGNS DEFINE THE REFERENCE POLARITY POINT A HAS 5V LESS THAN POINT B POINT A HAS 2V MORE THAN POINT B IF THE NUMBER V IS POSITIVE POINT A HAS V VOLTS MORE THAN POINT B. IF THE NUMBER V IS NEGATIVE POINT A HAS |V| LESS THAN POINT B

  23. THE TWO-INDEX NOTATION FOR VOLTAGES INSTEAD OF SHOWING THE REFERENCE POLARITY WE AGREE THAT THE FIRST SUBINDEX DENOTES THE POINT WITH POSITIVE REFERENCE POLARITY WHAT ENERGY IS REQUIRED TO MOVE 120[C] FROM POINT B TO POINT A IN THE CIRCUIT? THE CHARGES MOVE TO A POINT WITH HIGHER VOLTAGE -THEY GAINED (OR ABSORBED) ENERGY THE VOLTAGE DIFFERENCE IS 5V WHICH POINT HAS THE HIGHER VOLTAGE?

  24. ENERGY AND POWER 2[C/s] PASS THROUGH THE ELEMENT EACH COULOMB OF CHARGE LOSES 3[J] OR SUPPLIES 3[J] OF ENERGY TO THE ELEMENT THE ELEMENT RECEIVES ENERGY AT A RATE OF 6[J/s] IN GENERAL EXAMPLE A CAMCODER BATTERY PLATE CLAIMS THAT THE UNIT STORES 2700mAHr AT 7.2V. WHAT IS THE TOTAL CHARGE AND ENERGY STORED? CHARGE THE NOTATION 2700mAHr INDICATES THAT THE UNIT CAN DELIVER 2700mA FOR ONE FULL HOUR TOTAL ENERGY STORED THE CHARGES ARE MOVED THROUGH A 7.2V VOLTAGE DIFFERENTIAL THE ELECTRIC POWER RECEIVED BY THE ELEMENT IS 6[W] HOW DO WE RECOGNIZE IF AN ELEMENT SUPPLIES OR RECEIVES POWER?

  25. THIS IS THE REFERENCE FOR POLARITY IF VOLTAGE AND CURRENT ARE BOTH POSITIVE THE CHARGES MOVE FROM HIGH TO LOW VOLTAGE AND THE COMPONENT RECEIVES ENERGY --IT IS A PASSIVE ELEMENT IF THE REFERENCE DIRECTION FOR CURRENT IS GIVEN EXAMPLE GIVEN THE REFERENCE POLARITY THE ELEMENT RECEIVES 20W OF POWER. WHAT IS THE CURRENT? SELECT REFERENCE DIRECTION BASED ON PASSIVE SIGN CONVENTION REFERENCE DIRECTION FOR CURRENT PASSIVE SIGN CONVENTION POWER RECEIVED IS POSITIVE WHILE POWER SUPPLIED IS CONSIDERED NEGATIVE A CONSEQUENCE OF THIS CONVENTION IS THAT THE REFERENCE DIRECTIONS FOR CURRENT AND VOLTAGE ARE NOT INDEPENDENT -- IF WE ASSUME PASSIVE ELEMENTS

  26. We must examine the voltage across the component and the current through it S2 S1 UNDERSTANDING PASSIVE SIGN CONVENTION A A’ B B’

  27. CHARGES RECEIVE ENERGY. THIS BATTERY SUPPLIES ENERGY CHARGES LOSE ENERGY. THIS BATTERY RECEIVES THE ENERGY WHAT WOULD HAPPEN IF THE CONNECTIONS ARE REVERSED IN ONE OF THE BATTERIES?

  28. SUPPLIES POWER RECEIVES POWER DETERMINE WHETHER THE ELEMENTS ARE SUPPLYING OR RECEIVING POWER AND HOW MUCH WHEN IN DOUBT LABEL THE TERMINALS OF THE COMPONENT

  29. SELECT VOLTAGE REFERENCE POLARITY BASED ON CURRENT REFERENCE DIRECTION WHICH TERMINAL HAS HIGHER VOLTAGE AND WHICH IS THE CURRENT FLOW DIRECTION SELECT HERE THE CURRENT REFERENCE DIRECTION BASED ON VOLTAGE REFERENCE POLARITY

  30. COMPUTE POWER ABS ORBED OR SUPPLIED BY EACH ELEMENT P1 = 12W P2 = 36W P3 = -48W IMPORTANT: NOTICE THE POWER BALANCE IN THE CIRCUIT

  31. CIRCUIT ELEMENTS PASSIVE ELEMENTS VOLTAGE DEPENDENT SOURCES INDEPENDENT SOURCES CURRENT DEPENDENT SOURCES

  32. EXERCISES WITH DEPENDENT SOURCES DETERMINE THE POWER SUPPLIED BY THE DEPENDENT SOURCES TAKE VOLTAGE POLARITY REFERENCE TAKE CURRENT REFERENCE DIRECTION

  33. USE POWER BALANCE TO COMPUTE Io POWER ABSORBED OR SUPPLIED BY EACH ELEMENT POWER BALANCE NOTICE THE POWER BALANCE

More Related