Clemson ECE Laboratories PreLabs for ECE 211 Created

Clemson ECE Laboratories Pre-Labs for ECE 211 Created by Guneet Bedi on 09/03/2012 Last Updated: 12/15/2012 1

Clemson ECE Laboratories ECE 211 - Electrical Engineering Lab I Pre-labs for ECE 211 Guneet Bedi Created: 09/03/2012 Updated: 09/03/2012 2

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Clemson ECE Laboratories Introduction • This laboratory course operates in co-ordination with the companion lecture course, ECE 202, Electric Circuits 1. • It is intended to enhance the learning experience of the student in topics encountered in ECE 202. 4

Clemson ECE Laboratories Lab Objectives • Through this lab, students are expected to: 1. Gain proficiency in the use of common measuring instruments. 2. Compare theoretical predictions with experimental results and explain any differences. 3. Develop verbal and written communication skills through: a. Maintenance of succinct but complete laboratory notebooks and reports. b. Verbal interchanges with the laboratory instructor and other students. 5

Clemson ECE Laboratories Lab Objectives contd… 4. Enhance understanding of the basic electric circuit analysis concepts including: a. Independent and dependent sources. b. Passive circuit components (resistors, capacitors, inductors, and switches). c. Ohm’s law, Kirchhoff’s voltage law, and Kirchhoff’s current law. d. Power and energy relations. e. Thevenin’s theorem and Norton’s theorem. f. Superposition 6

Clemson ECE Laboratories Student Responsibilities • The student is expected to be prepared for each lab. • Active participation by each student in lab activities is expected. • The student is expected to ask the teaching assistant any questions he/she may have. • The student should understand the concepts and procedure of each lab. • The student should remain alert and use common sense while performing a lab experiment. • He/she is also responsible for maintaining a laboratory notebook. • Students should report any errors in the lab manual to the teaching assistant. 7

Clemson ECE Laboratories Lab Policy • Pre-Requisites: - MTHSC 108 and PHYS 122 • Co-Requisites: - ECE 202 • Attendance: - Attendance is mandatory and any absence must be for a valid excuse and must be documented. • Late Instructor: - If the instructor is more than 15 minutes late, students may leave the lab. • Pre-Lab: - Each lab has a “Preparation” section that should be read and completed prior to each lab. 8

Clemson ECE Laboratories Lab Policy contd… • Lab Records: - The student must keep all work in preparation of and obtained during lab in an approved notebook and prepare a lab report on selected experiments. • Late Work: - All full lab write-ups are due two weeks from the date lab is performed. Late work will NOT be accepted. • Final Exam: - The final exam will be given in lab on the last meeting. This exam will be closed-book and closed-notes. Use of calculator is permitted. 9

Clemson ECE Laboratories Grading Policy • The final grade is determined using the following criteria: Participation: - 10% Attendance: - 10% Pre-Lab: - 20% Lab Reports: - 40% Final Exam: - 20% • Grade Scale: A: 90%-100% B: 80%-89% C: 70%-79% D: 60%-69% F: <60% 10

Clemson ECE Laboratories The Laboratory Notebook • The laboratory notebook should: o Be kept in a sewn and bound or spiral bound notebook. o Contain the experiment’s title, the date, the equipment and instruments used, any pertinent circuit diagrams, the procedure used, the data, and the result analysis. o Contain plots of data and sketches when these are appropriate in the recording and analysis of observations. o Be an accurate and permanent record of the data obtained during the experiment and the analysis of the results. 11

Clemson ECE Laboratories The Laboratory Report • Your laboratory report must be clear and concise. • It should be typed on a word processor. • Use tables, diagrams, sketches, and plots, as necessary to show what you did, what was observed, and what conclusions you draw from this. • Your report should be the result of your individual effort. 12

Clemson ECE Laboratories The Laboratory Report-Format 13

Clemson ECE Laboratories Tentative Schedule 14

Clemson ECE Laboratories Contact Information • Instructor: Name: Guneet Bedi Email: gbedi@clemson. edu Office: 311 Fluor Daniel (EIB) Phone: (864)-556 -6048 Office Hours: As needed (email for appointment) • Lab Coordinator: Name: Dr. Timothy Burg Email: tburg@clemson. edu Office: 307 Fluor Daniel (EIB) Phone: (864)-656 -1368 15

Clemson ECE Laboratories Safety • Electricity, when improperly used, is very dangerous to people and to equipment. • This is especially true in an experimental or teaching laboratory where inexperienced personnel may use electrical equipment in experimental or nonstandard configuration. 16

Clemson ECE Laboratories Safety contd… • The knowledge and habit-forming experience to work safely around electrical equipment and the ability to design safe electrical equipment includes: o Learning the types of electrical injuries and damage. o How the electrical injuries can be prevented. o The physiology of electrical injuries. o Steps to take when accidents occur. 17

Clemson ECE Laboratories Physiology of Electrical Injuries • 1. 2. 3. There are three main types of electrical injuries: Electrical shock Electrical burns Falls caused by electrical shock • A fourth type, 'sunburned' eyes from looking at electric arcs, such as arc-welding, is very painful and may cause loss of work time but is usually of a temporary nature. • Other injuries may be indirectly caused by electrical accidents, e. g. , burns from exploding oil-immersed switch gear or transformers. 18

Clemson ECE Laboratories Prevention of Electrical Injuries • When hooking up a circuit, connect to the power source last, while power is off. • Before making changes in a circuit, turn off or disconnect the power first, if possible. • Never work alone where the potential of electric shock exists. • When changing an energized connection, use only one hand. Never touch two points in the circuit that are at different potentials. 19

Clemson ECE Laboratories Prevention of Electrical Injuries contd… • Know that the circuit and connections are correct before applying power to the circuit. • Avoid touching capacitors that may have a residual charge. The stored energy can cause a severe shock even after a long period of time. • Insulate yourself from ground by standing on an insulating mat where available. 20

Clemson ECE Laboratories After Accident Action • Shut off all power and remove victim from the electric circuit. • If the power cannot be shut off immediately, use an insulator of some sort, such as a wooden pole, to remove victim from the circuit. • If you are qualified in CPR, check for ventricular fibrillation or cardiac arrest. If either is detected, external cardiac massage should be started at once. • Notify EMS and the ECE Department at once. 21

Clemson ECE Laboratories After Accident Action contd… • Check for respiratory failure and take appropriate action. • Check for and treat other injuries such as fractures from a fall or burns from current entry and exit sites. • Investigations are always after accidents. As an engineer you will be involved as a part of the investigating team or in providing information to an investigator. 22

Clemson ECE Laboratories Emergency Numbers • Emergency (Fire/EMS): - 911 or 656 -2222 • Student Health Center: - 656 -2233 • ECE Department Office: - 656 -5650 23

Clemson ECE Laboratories Safety Video 24

Clemson ECE Laboratories Conclusions • As a professional engineer, it will be your responsibility to prepare yourself to do your job correctly. • Learn as much as you can "up front”. • You will find that as a practicing professional if you wait until the last minute, you might have to pay a very painful price emotionally, financially, and professionally. 25

Clemson ECE Laboratories Preparations for Next Week • Reading: - Read the section Use of Lab instruments and Appendix B, Fundamentals of Electrical Measurement, in the laboratory manual. • Writing: - In your laboratory notebook sketch the circuit diagram for each part of the procedure and create tables formatted to enter your data. 26

Clemson ECE Laboratories References • ECE 211 – Electrical Engineering Lab I. Latest Revised July 2010 27

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Clemson ECE Laboratories ECE 211 - Electrical Engineering Lab II Pre-labs for ECE 211 Guneet Bedi Created: 09/07/2012 Updated: 09/07/2012 29

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Clemson ECE Laboratories Introduction • Every engineer relies on equipment to drive and measure an electrical system under study. • These devices are rarely ideal, and have their own internal characteristics which must be accounted for in circuit design and analysis. • The internal characteristics of various devices often have a significant effect on circuit operation. • Students and engineers should understand the internal characteristics of the equipment they are using to more adequately predict actual operation in the lab. 31

Clemson ECE Laboratories Use of Laboratory Instruments-Ammeter • Ammeters are used to measure the flow of electrical current in a circuit. • For ammeters, it is important that their internal resistance be very small (ideally near zero) so they will not constrict the flow of current. • Ammeters must always be connected in series in a circuit, never in parallel with a voltage source. 32

Clemson ECE Laboratories Use of Laboratory Instruments-Voltmeter • Voltmeters are used to measure the potential difference between two points. • Since the voltmeter should not affect the circuit, the voltmeters have very high (ideally infinite) impedance. 33

Clemson ECE Laboratories Instrument Protection Rules • Set instrument scales to the highest range before applying power. • Be sure instrument grounds are connected properly. Avoid accidental grounding of "hot" leads. • Check polarity markings and connections of instruments carefully before connecting power. • Never connect an ammeter across a voltage source. • Do not exceed the voltage and current ratings of instruments. • Be sure the fuse and circuit breakers are of suitable value. 34

Clemson ECE Laboratories Lab Objective • The objective of this lab is to explore some of the internal characteristics for the NI- ELVIS workstations used in this course. • By the end of this lab: o The student should know how to determine the internal resistance of meters and sources. o The student should understand how the internal resistance of these instruments affects the measurements. 35

Clemson ECE Laboratories Equipment Needed • NI-ELVIS Series II workstation • Resistance substitution box • 1 kΩ Resistor 36

Clemson ECE Laboratories 37 NI-ELVIS Series II Workstation Features • Workstation Power Switch • Breadboard • Prototyping Board Power Switch • Function Generator (FGEN) • Digital Multimeter (DMM) Connectors • Power Supplies

Clemson ECE Laboratories NI ELVIS Instrument Launcher • Launch the Instrument Launcher by navigating to Start>>All Program Files>>National Instruments>>NI ELVISmx Instrument Launcher. 38

Clemson ECE Laboratories NI ELVIS Instrument Launcher-DMM 1. Display 2. Modes 3. Connections 4. Acquisition mode 5. Help 6. Run/Stop 7. Null offset 8. Mode 39

Clemson ECE Laboratories NI ELVIS Instrument Launcher-FGEN 1. Frequency Display 2. Waveform Selectors 3. Waveform Characteristics 4. Sweep Settings 5. Manual Mode 6. Signal Route 7. Sweep 40

Clemson ECE Laboratories NI ELVIS Instrument Launcher-VPS 1. Voltage Display 2. Manual Mode 3. Output Voltage Controls 4. Sweep Settings 1. Sweep 41

Clemson ECE Laboratories Procedure-Getting Started 1. Turn on computer. 2. Turn on NI-ELVIS power switch (right corner on the back). 3. Turn on the NI-ELVIS Prototyping Board Power switch (at upper right corner, on top). 4. Launch NI-ELVISMX INSTRUMENTS program. 5. Launch the NI-ELVIS DMM instrument. 6. Launch the NI-ELVIS VPS (Variable Power Supply) instrument. 7. Arrange the instruments on the computer screen for your convenience. 8. Set DMM to measure DC Volts. Specify the range to be 60 V. 42

Clemson ECE Laboratories Procedure-NULL OFFSET for Voltmeter • Electrical drift sometimes causes shifts in the ZERO point indicated by measurement instruments. • To eliminate the shift, the NI-ELVIS provides a NULL OFFSET function that subtracts the value indicated at the instant NULL OFFSET is turned on. • 1. 2. 3. To set the voltmeter’s NULL OFFSET: Plug leads into the DMM “VΩ” and “COM” jacks. Clip the leads together, let the voltage reading stabilize. Turn on “Null Offset”. 43

Clemson ECE Laboratories Procedure-DC Resistance of DMM Voltmeter • Set the VPS “Supply +” voltage to +10. 00 Volts. “STOP” the VPS. • Set up the circuit as shown in figure. • Use the NI-ELVIS DMM for the voltmeter and the VPS for the power supply. • Set the resistor R to 0Ω by shorting the resistor’s leads. • “RUN” the VPS and record the voltage indicated by the meter. • Remove the short across R. 44

Clemson ECE Laboratories Procedure-DC Resistance of DMM Voltmeter contd… • Increase the resistance R so that the meter reading drops by one half of the original value. • Record the final resistance R and measured voltage. • “STOP” the VPS. • Use the DMM ohmmeter to measure the actual resistance R. • Record the measured value. • From these readings, use voltage division to calculate RVi, the equivalent internal resistance of the voltmeter. 45

Clemson ECE Laboratories Procedure-DC Resistance of DMM Ammeter • Set the VPS “Supply +” voltage to +10. 00 Volts. • “RUN” the VPS and measure the actual voltage using the DMM voltmeter. Record the actual voltage. • “STOP” the VPS. • To use the DMM as an ammeter, move the DMM cables to “A” and “COM” and switch the DMM to measure DC Amps. • Set up the circuit as shown in figure. • Use the NI-ELVIS DMM for the ammeter and the VPS for the power supply. 46

Clemson ECE Laboratories Procedure-DC Resistance of DMM Ammeter contd… • • • Set the resistor R to 1 MΩ resistance. “RUN” the VPS. Record the resistance R and the current indicated by the ammeter. Adjust R to 100 kΩ. Record the resistance R and the current indicated by the ammeter. Continue to decrease the resistance R until the ammeter reading drops to one half of the original value. • Record the final resistance R and measured current. • Use the DMM ohmmeter to measure the actual final resistance R. • From these readings, use current division to calculate RAi, the equivalent internal resistance of the ammeter. 47

Clemson ECE Laboratories Procedure-Output Resistance of VPS Supply + • Set the VPS “Supply +” voltage to +0. 5 Volts. • Use the DMM to measure the actual voltage. • Record the actual voltage. • Construct the circuit shown in figure. 48

Clemson ECE Laboratories Procedure-Output Resistance of VPS Supply + contd… • • Adjust the resistor R to 10 kΩ. “RUN” the VPS. Record the resistance R and the measured voltage. Adjust the resistance R so that the meter reading drops to one half of the original value. • Record the R and V values. • From these readings, use voltage division to determine RVPS. Where, 49

Clemson ECE Laboratories Procedure-Output Resistance of FGEN • Construct the circuit shown in figure. • Set the FGEN to output a sine wave with p-p amplitude of 1. 41 V and frequency 100 Hz. • Set the DMM to measure AC Volts. Keep in mind that the voltmeter’s display shows the value of RMS voltage, where for a sinusoidal waveform, 50

Clemson ECE Laboratories Procedure-Output Resistance of FGEN contd… • • Adjust the resistor R to 100 kΩ. “RUN” the FGEN. Record the resistance and the measured voltage. Adjust the resistance R so that the meter reading drops to one half of the original value. • Record the R and V values. • From these readings, use voltage division to determine RFGEN, the equivalent internal resistance of the Function Generator. Where, 51

Clemson ECE Laboratories Lab 2 -Student Tasks • Students are required to submit a lab report on this experiment. • Students MUST strictly adhere to the format as described in the lab manual. • For the ‘Questions’ section of the lab report, the students are required to solve the problems given as a part of ‘Probing Further’ section of this lab in the manual. • Your report is due in TWO WEEKS from today. 52

Clemson ECE Laboratories Preparations for Next Week • Read the introductory material in the ECE 202 textbook describing the passive sign convention for circuit elements. • Review the lab manual section Use of Laboratory Instruments. • Calculate the values of voltage, current, and power absorbed/delivered for each circuit element in Figure 3. 1 (i. e. do Part 0 of the Procedure). • Sketch in your lab notebook the circuit diagrams to be used in each part of the procedure and have a table prepared for each part in order to record data. 53

Clemson ECE Laboratories References • ECE 211 – Electrical Engineering Lab I. Latest Revised July 2010. • Otago University Electronics Group-NI ELVIS II Orientation Manual. 54

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Clemson ECE Laboratories ECE 211 - Electrical Engineering Lab III Pre-labs for ECE 211 Guneet Bedi Created: 09/13/2012 Updated: 09/16/2012 56

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Clemson ECE Laboratories Introduction • Voltage and current values may be used to determine the power consumed (or provided) by an electrical circuit. • Electric power consumption is a very important factor in all electrical applications, ranging from portable computers to megawatt industrial complexes. • Thus, an understanding of power and how it is measured is vital to all engineers. 58

Clemson ECE Laboratories Electric Charge-A Brief Review • The charge is bipolar, i. e. electrical effects are described in terms of positive and negative charges. • The electric charge exists in discrete quantities, which are integral multiples of the electronic charge, 1. 6022× 10 -19 C. • Electrical effects are attributed to both the separation of charge and charges in motion. 59

Clemson ECE Laboratories Voltage • Whenever positive and negative charges are separated, energy is expended. • Voltage is the energy per unit charge created by the separation. • It can be expressed in differential form as: where, v=voltage in volts w=energy in joules q=charge in coulombs 60

Clemson ECE Laboratories Current • Electric current is defined as the rate of charge flow. • It can be expressed in differential form as: where i=current in amperes q=charge in coulombs t=time in seconds 61

Clemson ECE Laboratories Power • Power is the time rate of expending or absorbing energy. • Mathematically, energy per unit time can be expressed in differential form as: where p=power in watts w=energy in joules t=time in seconds 62

Clemson ECE Laboratories Power in terms of Voltage & Current so, where p=power in watts v=voltage in volts i=current in amperes 63

Clemson ECE Laboratories Passive Sign Convention • Whenever the reference direction for the current in an element is in the direction of the reference voltage drop across the element (as shown in figure), use a positive sign in any expression that relates the voltage to the current. • Otherwise, use a negative sign. 64

Clemson ECE Laboratories Use of Laboratory Instruments-Ammeter • Ammeters are used to measure the flow of electrical current in a circuit. • For ammeters, it is important that their internal resistance be very small (ideally near zero) so they will not constrict the flow of current. • Ammeters must always be connected in series in a circuit, never in parallel with a voltage source. 65

Clemson ECE Laboratories Use of Laboratory Instruments-Voltmeter • Voltmeters are used to measure the potential difference between two points. • Since the voltmeter should not affect the circuit, the voltmeters have very high (ideally infinite) impedance. 66

Clemson ECE Laboratories Lab Objective • By the end of this lab, the student should know: o How to make DC measurements of voltages and currents. o How to determine power dissipation/delivery for circuit elements, branches, and various combinations of elements and branches. 67

Clemson ECE Laboratories Equipment Needed • NI-ELVIS Series II workstation • Two 510Ω Resistors • One 1 kΩ Resistor 68

Clemson ECE Laboratories Procedure-Theoretical Calculation of Voltage, Current & Power • For the circuit given in figure, calculate the voltages across and currents through each circuit element. • Using these values, determine the power absorbed or delivered by each circuit element. 69

Clemson ECE Laboratories Procedure-Experimental Circuit Voltage Measurements 70 • Set up the circuit in figure. • Adjust the output of the DC power supply to 10 V. • Using the DMM function in the NI-ELVIS workstation measure the voltage across each individual circuit element. • For each measured voltage, determine the percent difference from theoretical value.

Clemson ECE Laboratories Procedure-Experimental Circuit Current Measurements • Set up the circuit in figure. • Adjust the output of the DC power supply to 10 V. • Using the DMM function in the NI-ELVIS workstation measure the current through each individual circuit element. • For each measured current, determine the percent difference from theoretical value. 71

Clemson ECE Laboratories Procedure-Experimental Circuit Power Calculation • Using your experimental voltage and current measurement data, calculate the power absorbed or delivered by each circuit element. • Compare this power obtained with the values obtained through theoretical circuit analysis. • Calculate the percent difference from theoretical values. 72

Clemson ECE Laboratories Lab 3 -Student Tasks • Students are required to solve the ‘Probing Further’ section, given in the lab manual, in their laboratory notebooks. • Lab notebooks are due on the same day as your report for lab 2. 73

Clemson ECE Laboratories Preparations for Next Week • Calculate the voltages and currents for each resistor shown in the circuit of Figure 4. 1 in your lab manual (i. e. do Part 0 of the Procedure). 74

Clemson ECE Laboratories References • ECE 211 – Electrical Engineering Lab I. Latest Revised July 2010. • Electric Circuits 8 th Edition by James W. Nilsson & Susan A. Riedel. 75

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Clemson ECE Laboratories ECE 211 - Electrical Engineering Lab IV Pre-labs for ECE 211 Guneet Bedi Created: 09/24/2012 Updated: 09/24/2012 77

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Clemson ECE Laboratories Introduction • B 2 Spice v 5 is an integrated circuit design, simulation, and analysis software • It contains a mixed mode simulator based partly on the Berkeley SPICE simulator and partly on the Georgia Tech XSPICE simulator • B 2 Spice v 5 is an application with two separate subprograms: the B 2 Spice main program, and the Database Editor • It allows you to perform realistic simulations on your circuit without the need of any physical component or any expensive test equipment 79

Clemson ECE Laboratories Lab Objective • This lab should give the student a basic understanding of how to use B 2 Spice to simulate circuit operating conditions. • After this lab, the student should be able to use B 2 Spice to solve or check basic circuit problems. 80

Clemson ECE Laboratories Equipment Needed • A computer with B 2 Spice loaded and ready to use. 81

Clemson ECE Laboratories Procedure-Theoretical Calculation of Voltage & Current • For the circuit given in figure, calculate the voltages across and currents through each resistor. 82

Clemson ECE Laboratories Procedure-Opening Software & Creating New Project • Double click on B 2 Spice. V 5 shortcut icon on desktop • The following window will appear • File->New->Project(Check Schematic & Enter Project Name)->Ok 83

Clemson ECE Laboratories Procedure-Placing Resistors • Common parts->Resistor(simple)(R) • Place resistor as desired on the workspace • Double click on the resistor placed to modify its default parameters • Right click on the resistor placed for more options(e. g. rotate clockwise) 84

Clemson ECE Laboratories Procedure-Placing Voltage Source • Common parts->Voltage Source(V) • Place the voltage source as desired on the workspace • Double click on the voltage source placed to modify its default parameters • Right click on the voltage source placed for more options(e. g. rotate clockwise) 85

Clemson ECE Laboratories 86 Procedure-Placing Ammeter/Voltmeter • Common parts->Ammeter(1)/Voltmeter(2) (Horizontal/Vertical) • Place the ammeter/voltmeter as desired on the workspace • Double click on the ammeter/voltmeter placed to modify its default parameters • Right click on the ammeter/voltmeter placed for more options(e. g. rotate clockwise)

Clemson ECE Laboratories 87 Procedure-Placing Ground • • Common parts->Ground(0) Place the ground as desired on the workspace Ground default parameters cannot be changed Right click on the ground placed for more options(e. g. rotate clockwise)

Clemson ECE Laboratories 88 Procedure-Connecting Circuit Components Press to draw circuit lines • On clicking the draw circuit lines symbol, one can draw circuit lines to connect circuit components together • To discontinue drawing the circuit line press esc

Clemson ECE Laboratories Procedure-Running Simulations Pause Simulation Run • After setting up the circuit and placing the meters in the proper positions, press Run to simulate the circuit • To stop simulation, click Simulation->Stop and Reset 89

Clemson ECE Laboratories Test Circuit 1 90

Clemson ECE Laboratories Test Circuit 2 91

Clemson ECE Laboratories 92 Test Circuit 3 How does V across & I through each resistor vary with the given combinations of resistor values?

Clemson ECE Laboratories Lab 4 -Student Tasks • Students are required to solve the ‘Probing Further’ section, given in the lab manual, in their laboratory notebooks. • Lab notebooks are due on the same day as your report for lab 2. 93

Clemson ECE Laboratories Preparations for Next Week • Read the material in the textbook that describes Kirchhoff's Voltage Law, Kirchhoff's Current Law, voltage division, current division, and equivalent resistance combinations. • Before coming to class, analyze each circuit and determine theoretical values that should be obtained during the lab. • Verify your calculations by performing B 2 Spice simulations for each circuit. • Record both your calculations and simulation results in your laboratory notebook. 94

Clemson ECE Laboratories References • ECE 211 – Electrical Engineering Lab I. Latest Revised July 2010. • B 2 Spice Version 5 User’s Manual by Thien Nguyen, Christopher Hsiong and Jon Engelbert © 1996 - 2005, Beige Bag Software, Inc. 95

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Clemson ECE Laboratories ECE 211 - Electrical Engineering Lab V Pre-labs for ECE 211 Guneet Bedi Created: 10/01/2012 Updated: 10/01/2012 97

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Clemson ECE Laboratories Introduction • An understanding of the basic laws of electrical voltages and currents is essential to electrical engineering. • Circuit analysis is dependent upon knowing the nature of the laws governing voltage and current characteristics. • This lab studies Kirchhoff's Voltage Law, Kirchhoff's Current Law, voltage division, current division, and equivalent resistance. 99

Clemson ECE Laboratories Series Equivalent Resistance 100

Clemson ECE Laboratories Parallel Equivalent Resistance 101

Clemson ECE Laboratories Voltage-Divider Circuit 102

Clemson ECE Laboratories Current-Divider Circuit 103

Clemson ECE Laboratories 104 Kirchhoff’s Current Law • The algebraic sum of all the currents at any node in a circuit equals zero. • Using the convention that currents leaving the node are considered positive and that entering the nodes are considered negative, the above circuit yields the four equations.

Clemson ECE Laboratories 105 Kirchhoff’s Voltage Law • The algebraic sum of all the voltages around any closed path in a circuit equals zero. • Here we elect to trace the closed path clockwise, assigning a positive algebraic sign to voltage drops. • Starting at node d leads to the expression:

Clemson ECE Laboratories Lab Objective • By the end of this lab, the student should understand KVL, KCL, voltage division, current division, and equivalent resistance combinations. 106

Clemson ECE Laboratories Equipment Needed • NI-ELVIS workstation • Resistance substitution box • Individual resistors (510Ω, 1 kΩ (2), 1. 5 kΩ, 2 kΩ (2), 3 kΩ, 3. 9 kΩ, 4. 3 kΩ, 5. 1 kΩ) 107

Clemson ECE Laboratories 108 Procedure-Equivalent Resistance • • Set up the circuit as shown in figure. Adjust the output of the DC power supply to 10 V. Measure and record the total current into the circuit. Using the measured current and voltage, determine the equivalent resistance of the parallel components in the circuit. • Replace the resistors with a resistance substitution box set to the equivalent resistance and measure the current as before. • Compare the experimentally determined equivalent resistance to theoretical value.

Clemson ECE Laboratories Procedure-Current Division & Kirchhoff's Current Law (KCL) • Set up the circuit as shown in figure. • Adjust the output of the DC power supply to 10 V. • Begin with R 2=510Ω and measure the currents I 1, I 2 and I 3. • Repeat with R 2=1 kΩ, 2 kΩ, 3 kΩ, 4. 3 kΩ and 5. 1 kΩ. • Compare the measured currents to those calculated using current divider relation. • Determine whether or not each set of measurements agrees with KCL. 109

Clemson ECE Laboratories Procedure-Voltage Division • Set up the circuit as shown in figure. • Adjust the output of the DC power supply to 10 V. • Begin with R=510Ω and measure the voltage across each resistor. • Repeat with R=1 kΩ, 2 kΩ, 3 kΩ, 4. 3 kΩ and 5. 1 kΩ. • Compare the measured voltages to those calculated using the voltage divider relation. 110

Clemson ECE Laboratories Procedure-Kirchhoff’s Voltage Law (KVL) (Single Loop) • Set up the circuit as shown in figure. • Adjust the output of the DC power supply to 10 V. • Measure the voltage across each component. • Compare the measured voltages to those calculated using the voltage divider relation. • Determine whether or not your measurements agree with KVL. 111

Clemson ECE Laboratories Procedure-Kirchhoff’s Voltage Law (KVL) (Multiple Loops) • Set up the circuit as shown in figure. • Adjust the output of the DC power supply to 10 V. • Measure the voltage across each component in loop 1. • Repeat for loop 2 and 3. • Compare your measured values with the terms in the KVL equation written for each loop. • Determine whether or not your measurements agree with KVL. 112

Clemson ECE Laboratories Lab 5 -Student Tasks • Students are required to submit a lab report on this experiment. • Students MUST strictly adhere to the format as described in the lab manual. • For the ‘Questions’ section of the lab report, the students are required to solve the problems given as a part of ‘Probing Further’ section of this lab in the manual. • Your report is due in TWO WEEKS from today. 113

Clemson ECE Laboratories Preparations for Next Week • Read the material in the textbook that describes The venin's equivalence theorem and maximum power transfer. 114

Clemson ECE Laboratories References • ECE 211 – Electrical Engineering Lab I. Latest Revised July 2010. • Electric Circuits 8 th Edition by James W. Nilsson & Susan A. Riedel. 115

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