Experiment #2: A.C. CircuitsReference: Simpson, Ch 2, Appendices A , C, & E
Objective: To provide experience with A.C. Ohm's law, to demonstrate the frequency dependence of reactance and impedance, and to investigate the properties of simple filter circuits.
Procedure: All the voltages in this experiment will be measured using the oscilloscope, while the frequencies will be measured with the counter. Be sure its vertical gain control is in the calibrated position. Refer to the previous description.
B. At each of 10 different frequency settings between 1 kilohertz and 100 kilohertz (1,2,4,7,10,20,40,70,100kHz), set (the output voltage of the signal generator) to 2.00 as measured by the oscilloscope and then measure and record along with the frequency the peak-to-peak voltages for and (the voltages across R, C, and the generator). Make all three measurement at the same frequency before going to another, and make them without changing the generator amplitude setting.
C. Results and Analysis
B. For 10 frequencies between 2KHz and 40KHz, measure and record the peak-to-peak voltage for V and V
Note: You should observe the VĂ to go through a definite peak (about a factor of VĂ ) over this range. If you observe no such behavior, or if your peak is less pronounced, consult the supervisor.
C. Graph VĂ over the range. The spread of the peak is related to the "Q" of the circuit, while the frequency of the greatest voltage is the resonant frequency. From your graph, estimate the resonant frequency and compare it with the value computed from theoretical considerations.
D.Â Note that the sum of the values VĂ at any frequency setting. Explain why this is not a violation of Kirchoff's law of voltages.
E. Rearrange the circuit so that the capacitor and inductor are adjacent as shown below:Æ(# Connect the signal generator as indicated by VĂ , and observe the voltage VĂ as the frequency is adjusted over the 2©20 KHz range. Describe qualitatively what you see. At the frequency of minimum VĂ , observe the value of VĂ . Explain why VĂ alone is much greater than VĂ
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