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Unformatted text preview:Experiment Six: Measurement of AC Voltage and Current "mush..- Engr 361 Section 1 Informal 10/21/2013 ' 10/28/2013 Introduction This experiment deals with the measurement of AC voltage and current. These goals are accomplished by the study of four part experiment. The parts are calculation, implementation of the designed voltmeter, KVL in an AC circuit, and Discussion/ Analysis. All of the instruments used in the experiment include: sine wave _ generator/Tektronix CFG250 or B&K Precision 4007DDS, oscilloscope, circuit board, R- L-C pre—mounted components, digital multimeter/ Fluke Model 37, DC micro-ampere meter, decade resistance box, 200k ohm resistor, diode/ 1N914, isolation transformer, voltage step-up transformer, Counter/ Tektronix CFC250. All of these steps lead to the main result of understanding and working with AC circuits and their measurements. Major Part As stated before, this experiment is all about the measurement of AC voltages and currents. The ﬁrst part is centered on the calculation and the ability to wire Figure 6 as an AC voltmeter with applied voltage of lOvrms. This lays the foundation for understanding the basic circuitry of an AC voltmeter. Figure ﬁve and its example are what set the stage for these calculations and those needed between Vavg and Vrrns later though. The second part deals with the actual implementation of the designed voltmeter in part one. This is a voltmeter the can deal with O—25Vrms and uses a 0-50 micro ammeter. The average value voltage is then found by this implementation and multiplied by 2.22 to get the average value voltages. Increments of SV are taken from 0 to twenty- ﬁve volts. One note to add to this section of theory is that the micro ammeter used will usually "clip" voltages for anything above lOVrms so the push-button should be depressed to ﬁnd valid voltage measurements. Lastly for this part, seven sketches are taken to include the signal (one sketch), resistor (two sketches), diode (two sketches), and the meter movement (two sketches). These sketches are taken in both AC and DC mode to show the phase shift physically or "electrically" in the experimenter's case in the lab procedure. Part three is the next piece of information to reference; it deals with the idea of KVL in an AC circuit. The circuit of ﬁgure seven is wired with the different components of resistance, capacitance, inductance, and meter movement. DVM and the student constructed voltmeter of Part II are used here to measure and check the rrns magnitudes of Vr, VI, and Vc. The question that was raised about reversing the voltmeter leads here is answered by stating that this change in polarity doesn't have any effect on the meter deﬂection. Here the experimenter ﬁnds the phase angle between Vr/Vin, WW], and Vr/Vc. The lead or lag of voltages versus the resistor voltage is duly noted here and then these three different realized circuits are sketched. Finally, the reader gets to the last part of the experiment and the discussion or analysis part of all the ﬁndings. Question (a) has already been answered above and therefore will still not effect the meter deﬂection. The second statement/ question (b) of the discussion analysis asks for a comparison of values, which has been done, and the student ﬁnds that any error is most likely due to instrumental calibration or human error. Part (0) makes one realize thatﬂu'ase shift is a measure of, usually two sine, waves that don't peak at the same time or cross the time axis at the same time. The phasor diagram is drawn and added to the end; KVL is veriﬁed/ Vin leads. (d) is also included at the end. e)? Results These are added as appendices and graphs at the end of the lab report. Data Summary Sheets ENGR 361 and ENGR 363 Experiment Six B_al_'tl: Calculations (a) Voltmeter design: Series resistance R = 226 i000 a (b) Circuit analysis of RLC circuit: VR = Z M i; ; Phase shift between VR and Vin: 0 = V 1': a ygym mun/"C P II: Voltmeter Construction and Measurements '( 5 (a) No data required (b) Calibration data 011A 9M1 .1 goomnaooﬂ- 230'wa ﬂMA 43000041; I O I ZnA 12000032761222 itM- H : 3.63x211Z7i." 56m DVM (rms volts) Student designed meter (rms volts) Q k 375 S 3s 1 r: (d), (e) Waveform Observations Exp. 6 Pg. 15 8M Observe: mel - Sketches 4, 4a: H26 x vin - Sketch #1 Vi..(avg) = vR - Sketches 2, 2a: VR(avg) = . V D - Sketches 3, 3a: VDGNE) = 'Ié' ' 1 8 Vmeter(avg) = __L_£;..7.i;'—— Part III: Veriﬁcation of KVL at 500 Hz (a) Voltage measurements Student designed voltmeter (rrns Reverse leads (comments): RM? you (b) Phase measurements Observe: Phase between: Angle (degrees) Which voltage leads? na- Exp. 6 Pg. 16 III-II!- ==e:::%r A 1 t \ ' "HIHIMINIH-H "I'VEII'IW. l-Iﬂ'llilﬂll IIIIUIIIKIII III-IIIIIIII Vertical Settings: Horizontal Setting: Ch. 1 volts/div: S \/ Sec/div: - 54 Ch. 2 volts/div: lﬂﬂlﬂiﬂl _ I'll-III. II III-IIIIIIII III-IEIIIIII Vertical Settings: Horizontal Setting: Ch. 1 volts/div:_____S_L/____ Sec/div: . 5 X Ch. 2 volts/div: Figure: 2 Sketch of 4 5i? Exp. 6 Pg. 17 IIIIIIIIIIII Inn-lﬁallmnl Iﬂﬂllﬂﬂllﬂﬂ mnmunnmnnnm III-Iﬂllﬂi II II .- Vertical Settings: Horizontal Setting: C' Ch.1volts/djv: J v Sec/div: 9 I><Ch. 2 volts/div: Figure: __3__ Sketch of D! Vg III-IEIIIIII IIIIIEIIIIII Iﬂﬂllﬂ$llnﬂl Immnnumnnmm IIHIQIUIHHH / IIIIIIIIII Vertical Settings: Horizontal Setting: Ch. 1 volts/div:___gi__ Sec/div: S M011. 2 volts/div: Exp. 6 Pg. 18 IIIIIIIIIIII Inﬁllﬁﬂllﬂﬂl Inn-It'lluul Human magnum iii-iuulﬂill IIIIIIIIIIII Vertical Settings: Horizontal Setting: F Ch. 1 volts/div: \/ Sec/div: :XkCh. 2 volts/div: Figure: 9 Sketch of J B IIIIIEIIIIII IIIIIIIIIIII Ina-lasing:- gmnngﬁmnlnmn liulluiliiiu IIIIIIIIIIII Illlllllllll III-IEIII-II Vertical Settings: Horizontal Setting: Ch. 1 volts/div: i \/ sec/div; .g y Ch. 2 volts/div: AC, \) Figure: é Sketch of ________¥¥T__— Exp. 6 Pg. 19 IIIIIEIII Ill-IEJII Inn-linll, Engaginggn IIIIIEIIH IIIIIIIII Vertical Settings: Horizontal Setting: \ Ch. 1 volts/div: 'sv Sec/div: - 9 )(oh. 2 volts/div: Figure: 7 Sketch of I M g \' pg III-IIIIIIII lull-tailing mmlllwnnllmn mmmnmmnmnmmH mumumuumnmn "IMMIIINIWII IINHIIIUEIII III-IIIIIIII Vertical Settings: Horizontal Setting: Ch. 1 volts/div: 2 ____________. Sec/div: \ ; Ch. 2 volts/div:__;____ Figurezj' Sketch of We a 0d" \J Rsi U; lq Exp. 6 Pg. 20 / .'Ver/tiéL-uevmvyk A. Other switch settingé 5: remarks . Sketch of Other switch settiﬁgsf emarks g) I Figure . Sketch of ' ' ' I I 0! ILA/4 In I 6%; 9 Name: Grading Sheet for Experiment Six Summary: Goals and objectives stated ? (5) Experimental concept and procedure? (5) P I: Calculation —— (a) 0—25 Vrms voltmeter design? (10) (b) Series RLC circuit voltages and phases (5) Part 111: RLC Network (a) Branch voltages using voltmeter (8) (b) Phase angles between resistor voltage and 1. Applied voltage (4) 2. Inductor voltage (4) Report Format: Organization (5) Mechanics (grammar, spelling, etc.) (5) Expression of Ideas (5) Part 11: AC Voltmeter (a) Construct voltmeter Ugh: _. 5(b) Calibration data (5) the, C :gic) Use of scope to observe diode, resistor, and meter voltages; average values (10) Part IV: Analysis and Comparison of Results to Theory? (a) Reversing connections? (5) _— (c, \3 *6" VW :3.de #(b) Compare RLC results (5) Cf \F (c) Phasor diagram (with VR as ph e reference), Kirchhoﬁ" 5 Voltage Law (5 i (d) Calculate L and C (5) .. (6) Square wave measurement (5)