meas (1) calc calc I meas 100% (2) Diff I meas

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Jayson McCormick
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1 Lab Experiment No. Ohm s Law I. Introduction In this lab exercise, you will learn how to connect the to network elements, how to generate a VI plot, the verification of Ohm s law, and the calculation of element power. II. Experiment Procedure Schematic diagrams for resistive networks N through N 5 are shown in Figures through 5 on the following pages. Current directions for each element are shown with line arrows. The actual element connections are also shown. The correct way to connect the as an ammeter (AM) and as a voltmeter (VM) is shown in Figure (c) for reference. Resistor VI plot. In network N, the 0KΩ resistor is connected to the Agilent E60A power supply. The supply voltage is to be varied from 0 volts to 0 volts with the voltage steps shown in Table. i. and record the of. Place the in Table where indicated. ii. Use the digital multi-meter () to measure the voltage across and the current through for each of. Record these measurements in Table where indicated. iii. Use Excel to generate a graph of V R (linear scale vertical axis) plotted against I R (linear scale horizontal axis). Calculate the of the slope of this plot and compare to the measured of. Calculate the difference in percent (Diff R ) between these two s with the measured as the base. Record these s in Table where indicated. Verification of Ohm s law. Networks N through N 5 contain various combinations of resistors and voltage sources. Data tables are provided for each network. i. For each network, use the digital multi-meter () to measure the voltage across and the current through each element (dc voltage sources and resistors), and the of each resistor. Record these measurements in the tables where indicated. Again, the correct way to connect the as an ammeter (AM) and as a voltmeter (VM) is shown in Figure (c). ii. Verify the validity of Ohm s law by calculating each resistor current from its measured voltage and the measured of its resistance. That is, from Ohm s law, I calc V meas meas () where V (meas) is the voltage measured across resistor R i in volts, R i (meas) is the measured of R i s resistance in ohms (Ω), and I (calc) is the calculated in amps of the current through R i. Record these calculated s in the tables where indicated. iii. Verify the accuracy of Ohm s law by calculating the percent difference ( ) between the measured resistor current (I (meas)) and calculated current (I (calc)) with the measured as the base. In other words Diff I I meas % I calc I meas 00% () Record these differences in the tables where indicated. iv. Calculate the power dissipated by each resistor and delivered to or from each voltage source. The power in Watts delivered to a network element e is computed from Pe Ve Ie () where V e is the voltage drop across e, I e is the current through e, and is the power delivered to the element. If is negative, power is delivered from the element to the network. Calculate using measured variables. Record these powers in the tables where indicated.

2 III. Lab Report The report for this lab experiment must be word-processed and contain the following items Title Page. Introduction. Procedure. Results. Discussions. Suggest useful applications for Ohm s law as studied in this experiment. Conclusion. Are all measured and calculated currents within resistor tolerance? List those that are not. Explain how resistor variations produce differences between measured and calculated currents. (c) Which method of determining resistor currents (measurement versus calculation) yields more accurate results? Explain. (d) Which method is more convenient? Explain. (e) Explain how you would convince your boss (via a sales pitch) to use on method over the other. Strengthen your sales pitch with solid engineering practice and mathematical reasoning. Appendix. References.

3 IV. Resistive Networks. Network N. Agilent E60A V 0K N (AM) I I R (AM) (VM) V 0K VR (VM) (c) Figure Network N (c) connections Table d variables from N V R I R (meas) (Ω) Slope of VI plot (Ω) Diff R

4 . Network N. Agilent E60A V K 9V K N K Figure Network N Table N measured and calculated variables KΩ KΩ KΩ 9V N/A N/A

5 . Network N. Agilent E60A V 5V 00K 50K 0K N Figure Network N Table N measured and calculated variables 00KΩ 50KΩ 0KΩ 5V N/A N/A

6 . Network N. Agilent E60A V V 7K 00K V 5V 0K N Figure Network N Table N measured and calculated variables 7KΩ 0KΩ 00KΩ V N/A N/A V 5V N/A N/A

7 5. Network N 5. Agilent E60A V 0K 0K 0V K 5V V N 5 Figure 5 Network N 5 Table 5 N 5 measured and calculated variables 0KΩ 0KΩ KΩ 0V N/A N/A V 5V N/A N/A

Experiment #6. Thevenin Equivalent Circuits and Power Transfer

Experiment #6. Thevenin Equivalent Circuits and Power Transfer Experiment #6 Thevenin Equivalent Circuits and Power Transfer Objective: In this lab you will confirm the equivalence between a complicated resistor circuit and its Thevenin equivalent. You will also learn