EGR214 Laboratory Activities 1School of EngineeringGrand Valley State UniversityEGR 214 – Laboratory #11Th´evenin ModelsObjectives• To investigate how well a Th´evenin model can be used to describe a var ie ty of physical circ uits andcomponentsPre-Lab Assignment1. Read through the entire lab.Pre-Lab DeliverablesThese deliverables are due at the beginning of your laboratory period. Your instructor will verifythese deliverables as you enter the laboratory and will use them to construct your laboratory grade.1. None for this labAdviceAs you work through this (and subse quent) laboratories, SHOW YOUR RESULTS TO YOUR INSTRUC-TOR AS YOU OBTAIN THEM. Your instructor will be able to guide you towards the “correct” (or expected)results, thus saving you from having to re -do large portions of the laboratory.Part I – 9V Alkaline Battery1. Obtain a 9V alkaline battery from your lab instructor1.2. Construct a table of values with four columns:• Resistor load circuit schematic• Total load resistance (Ω)• Measured voltage (V)• Derived load current (A)3. Fill in the columns by connecting va rious res istive load circ uits to the battery and measuring thevoltage output of the battery.You should aim for nearly-equally-spaced values of LOAD CURRENT (not resistance) between 0mAand 100mA (i.e., 0mA, 10mA, 20mA, etc.) Verify that the power rating of your resistors are appropria te.Your resistor load circuit should use resistors in series or parallel to keep each resistor’s power dissipationwithin its rating, and to achieve the desired resistance value. For exa mple, here is a resistive load circuitdesigned to conduct 100mA at 9V and not dissipate more than 0. 25W in any resistor:1If no 9V batteries are available, use a 1.5V AA battery and adjust the lab procedure as appropriate.Copyrightc 2010 Padnos College of Engineering & ComputingEGR214 Laboratory Activities 2330Ω 330Ω 330Ω 470ΩDraw this type of schematic in the fir st column of your table of values .4. If the voltage drops below the expected value, your load resistance will be too high and the currentdraw will not be as expected. If the actual current is within ±5mA of the expected value, then don’tworry abo ut it. Otherwise, adjust your load resistance as appropriate.5. From your table of values, construct a graph of measured voltage (Y-axis) as a function of load current(X-axis). Identify the region of the gr aph (i.e., the range of load current) which is approximately linearand construct a best-fit straight line model (i.e., linear regre ssion) OVER THIS REGION ONLY.Ensure you identify the slope, intercept, and the corre lation coe fficient on your graph.• In your repor t include:– The table of values you constructed– Your graph of voltage as a function of load current, along with the linear regression line and 3parameters6. Using your linear regression, construct a Th´evenin model of the battery.• In your report include the schematic of your T h´eve nin model as well as a discussion of how well themodel describes the battery’s operation and the range of load currents over which the model is accurate.Part II – 7805 Voltage Regulator1. A voltage regulator is an integrated circuit designed to maintain a constant output voltage regardlessof input voltage or output curr e nt (within reasonable limits). Its operation is similar in application toa pneumatic pressure regulator which maintains cons tant ou tput air pressure regardless of input airpressure o r air flow.Repeat the procedure of Part I using a 7805 5V voltage reg ulator configure d as shown below:7V7805100nF 100nFIN OUTGNDvoutThe 78 05 has the following pin diagram:Copyrightc 2010 Padnos College of Engineering & ComputingEGR214 Laboratory Activities 32. The output of the 7805 sho uld be 5V thus design your res istor loads acc ordingly for load currents ofup to 10 0mA.3. Submit the same deliverables as required in Part I.Part III – Operational Amplifie r1. Repeat the procedure of Part I using a 74 1 operational amplifier configured as shown below:+-+9V7324610kΩ10kΩ10kΩvout741The output should be 7V-8V when there is 0A load current.2. Submit the same deliverables as required in Part I.Part IV – Solar Cell1. Repeat the procedure of Part I using a solar cell (obtain fr om your lab instructor).2. Submit the same deliverables as required in Part I.At The End Of The Laboratory• Clean up your workstation, return all wire, components, etc. to the PROPER locations.• Disconnect all cables and return them to their PROPER locations.• Turn off all test equipment and replace the cover on the osc ill oscope.• Make sure you clearly understand the laboratory deliverables and their due date.Copyrightc 2010 Padnos College of Engineering & ComputingEGR214 Laboratory Activities 4Laboratory DeliverablesYou are to submit a brief technical report by the beginning of the next laboratory. Your report mustcontain a thorough discussion of your findings, including:• Your names, the date, the laboratory number, your laboratory section, etc.• Resp onses to the bulleted statements in the body of the laboratory procedure. Your responses shouldbe full English statements, structured to match the laboratory procedure, so that it is eas y for your in-structor to re ad and understand. Mathematical derivations must be clear, well-reasoned, and referenceactual measurements made in the laboratory.Each group is responsible for handing in one report.Copyrightc 2010 Padnos College of Engineering &