pasco软件实验手册电磁学44lr circuit

1、P44 - page * arabic: Physics Lab ManualVol. 2PASCO scientific LR CircuitScience WorkshopPASCO scientific page * arabic8Physics Experiment Library: 06020Science WorkshopVol. 2P44 LR CircuitP44 - page * arabic1996, PASCO scientificdgdg1996, PASCO scientificP44 - page * arabic8实验Experiment P44: LR Circ

2、uit电路 (Power Amplifier, Voltage Sensor)（功率放大器，电压传感器）Concept: circuits概念：电路Time: 30 m时间：30mSW Interface接口: 700Macintosh file:文件：P44 LR CircuitWindows file: 文件：P44_LRCI.SWSEQUIPMENT NEEDED所需仪器Science Workshop Interface科学工作室接口Power Amplifier功率放大器(2) Voltage Sensors 电压传感器LCR Meter (optional)计（选用）Multime

3、ter万用表(2) Patch Cords 接插线FROM AC/DC ELECTRONICS LAB*来自AC/DC电子学实验室resistor, 电阻，10 ohm (10 _)(2) wire lead, 引线，5 inch 英寸(*The AC/DC Electronics Laboratory is PASCO EM-8656.) (*The AC/DC Electronics Laboratory is AC/DC电子学实验室是 PASCO EM-8656.)PURPOSE目的This activity investigates the voltages across the in

4、ductor and resistor in an inductor-resistor circuit (LR circuit), and the current through the inductor so that the behavior of an inductor in a DC circuit can be studied. 本实验将研究一个电感-电阻（LR）电路中的电感和电阻两端的电压及通过电感的电流，由此可以研究在LR电路中的电感的行为。THEORY原理When a DC voltage is applied to an inductor and a resistor in

5、series a steady current will be established: 当向串联的电感和电阻两端施加一个直流电压时，将产生一个稳定电流：where Vo is the applied voltage and R is the total resistance in the circuit. But it takes time to establish this steady-state current because the inductor creates a back emf in response to the rise in current. The current

6、will rise exponentially: 在这里，Vo是所施加的电压，R是电路中总的阻抗。但是形成这个稳恒电流需要花费一定的时间，因为电感会随着电流的增大而产生一个反电动势。电流将按指数规律增加：where L is the inductance and the quantity is the inductive time constant. The inductive time constant is a measure of how long it takes the current to be established. One inductive time constant is

7、 the time it takes for the current to rise to 63% of its maximum value (or fall to 37% of its maximum). The time for the current to rise or fall to half its maximum is related to the inductive time constant by 在这里，L是感应系数，参数是感应时间常数。感应时间常数是形成稳恒电流所花费的时间长短的量度。感应时间常数是电流增加到最大值的63%（或降低到最大值的37%）所花费的时间。电流增加或

8、降低到最大值的一半所花费的时间与感应时间常数的关系可以表示为：Since the voltage across a resistor is given by , the voltage across the resistor is established exponentially: 因为电阻两端的电压，所以电阻两端的电压可以用下面的指数式表示： Since the voltage across an inductor is given by , the voltage across the inductor starts at its maximum and then decreases e

9、xponentially: 因为电感两端的电压，所以电感两端的电压从最大值开始，并按指数规律下降：After a time t , a steady-state current Imax is established and the voltage across the resistor is equal to the applied voltage, Vo. The voltage across the inductor is zero. If, after the maximum current is established, the voltage source is turned of

10、f, the current will then decrease exponentially to zero while the voltage across the resistor does the same and the inductor again produces a back emf that decreases exponentially to zero. In summary:经过时间t 之后，就形成了一个稳恒电流Imax。电阻两端的电压就等于所施加的电压Vo电感两端的电压为零。如果在形成了一个最大电流后，关掉了电源，则电流以及电阻两端的电压将按指数规律下降到零；电感会再次

11、产生一个反电动势，这个电动势也将按指数规律下降到零。概括的说：DC Voltage applied:DC Voltage turned off: At any time, Kirchhoffs Loop Rule applies: The algebraic sum of all the voltages around the series circuit is zero. In other words, the voltage across the resistor plus the voltage across the inductor will add up to the source

12、voltage.任何时候，都适用Kirchhoffs回路规则：围绕串联电路的所有电压的代数和为零。换句话说，电阻两端的电压与电感两端的电压加起来等于电源电压。PROCEDURE 步骤In this activity the Power Amplifier provides voltage for a circuit consisting of an inductor and a resistor. The Voltage Sensors measure the voltages across the inductor and resistor. The Signal Generator pro

13、duces a low frequency square wave that imitates a DC voltage being turned on and then turned off. 在这个实验中，功率放大器将向一个电感和电阻构成的电路提供电压。电压传感器将测量电感和电阻两端的电压。信号发生器将产生一个低频方波，来模拟一个打开又关掉的直流电压。The Science Workshop program records and displays the voltages across the inductor and resistor as the current is establi

14、shed exponentially in the circuit. You will use the graph display of the voltages to investigate the behavior of the inductor-resistor circuit. 当电路中按指数规律形成电流时，科学工作室程序将记录并显示电感和电阻两端的电压。你将利用电压的图表显示来研究这个电感-电阻电路的行为。PART IA: Computer Setup计算机设置1.将 ScienceWorkshop 接口连接到计算机上，打开接口，然后打开计算机。2.将一个电压传感器连接到模拟通道A，

15、这个传感器就是“电压传感器A”； 将第二个电压传感器连接到模拟通道B，这个传感器就是“电压传感器B ”。3.将功率放大器连接到模拟通道C，将电源插线插入功放的背面，然后把它连接到一个合适的插座上。4.打开如下命名的ScienceWorkshop文件：1.Connect the Science Workshop interface to the computer, turn on the interface, and turn on the computer. 2.Connect one Voltage Sensor to Analog Channel A. This sensor will b

16、e “Voltage Sensor A”. Connect the second Voltage Sensor to Analog Channel B. This sensor will be “Voltage Sensor B”.3.Connect the Power Amplifier to Analog Channel C. Plug the power cord into the back of the Power Amplifier and connect the power cord to an appropriate electrical outlet.4.Open the Sc

17、ience Workshop document titled as shown :MacintoshWindowsP44 LR CircuitP44_LRCI.SWSThe document opens with a Graph display of Voltage (V) versus Time (sec), and the Signal Generator window which controls the Power Amplifier. 文件将打开并带一个电压(V)时间(sec)的图表显示和一个控制功率放大器的信号发生器窗口。Note: For quick reference, see

18、 the Experiment Notes window. To bring a display to the top, click on its window or select the name of the display from the list at the end of the Display menu. Change the Experiment Setup window by clicking on the Zoom box or the Restore button in the upper right hand corner of that window.) 注意：欲快速

19、参考，请参见实验注释窗口。欲将一个显示图放至前台，单击其所在窗口或从显示器底部的菜单栏中选择该显示图的名称。单击窗口右上角的扩大框或恢复按钮来改变实验设置窗口的大小。5.The Sampling Options for this experiment are: Periodic Samples = Fast at 10000 Hz, Start Condition = Ch. C voltage at 0 volts, and Stop Condition = Time at 0.02 seconds.6.The Signal Generator is set to output 3.00 V

20、, square AC Waveform, at 50.00 Hz. 信号发生器被设置为输出3.00VAC ，50.00Hz的AC方波波形。The Signal Generator is set to Auto so it will start automatically when you click MON or REC and stop automatically when you click STOP or PAUSE. 信号发生器被设置为自动，因此当你单击REC或MON时，信号输出将自动开始；当你单击停止或暂停时，信号输出将自动停止。7.Arrange the Graph displa

21、y and the Signal Generator window so you can see both of them. 调整示波器显示和信号发生器窗口的位置，以便你可以看到它们两个。PART II: Sensor Calibration and Equipment Setup传感器校准和仪器设置You do not need to calibrate the Power Amplifier or Voltage Sensor. 你无须校准电压传感器或功率放大器。1.Put the iron core into the inductor coil on the AC/DC Electron

22、ics Lab circuit board.将铁芯放入AC/DC电子学实验室线路板上的电感线圈中。2.Connect a 5 inch wire lead between a component spring next to the top banana jack, and the component spring at the right hand edge of the inductor coil on the circuit board.在上面的香蕉插孔旁边的元件弹簧和线路板上电感线圈右边的元件弹簧之间，连接一根5英寸引线。3.Connect the 10 _ resistor (bro

23、wn, black, black) between the component spring at the left hand edge of the inductor coil and the second component spring to the left of the top banana jack. 在电感线圈左边的元件弹簧和上面的香蕉插孔左边的第二个元件弹簧之间，连接一个10欧姆（棕色，黑色，黑色）电阻。4.Connect another 5 inch wire lead between the component spring nearest to the one in wh

24、ich one end of the 10 _ resistor is connected and a component spring nearest to the bottom banana jack at the lower right corner of the circuit board.在离10欧姆电阻的一端所连接的元件弹簧最近的那根弹簧，和离线路板右下角的香蕉插孔最近的元件弹簧之间，连接另一根5英寸引线。(See the manual for a diagram.)（见手册中的图示）5.Put alligator clips on the banana plugs of both

25、 Voltage Sensors. Connect the alligator clips of Voltage Sensor “A” to the component springs at both sides of the inductor coil.将鳄鱼夹夹在两个电压传感器的香蕉插头上，然后把电压传感器A的鳄鱼夹连接到电感线圈两端的元件弹簧上。6.Connect the alligator clips of Voltage Sensor “B” to the wires at both ends of the 10 _ resistor. 电压传感器B的鳄鱼夹连接到10欧姆电阻两端的引

26、线上。7.Connect banana plug patch cords from the output of the Power Amplifier to the banana jacks on the AC/DC Electronics Lab circuit board. 将来自功率放大器输出端的香蕉插头接插线连接到AC/DC电子学实验室线路板上的香蕉插孔中。PART III: Data Recording数据记录1.Use a multimeter to measure the resistance of the inductor coil on the AC/DC Electroni

27、cs Lab circuit board. Record the coil resistance in the Data section.用万用表测量AC/DC电子学实验室线路板上的电感线圈的阻抗，并将线圈的阻抗值记录在数据一节中。2.Use a multimeter to measure the resistance of the 10 _ resistor. Record the measured resistor value in the Data section.用万用表测量10欧姆电阻的电阻值，并将测量的电阻值记录在数据一节中。(Optional: If you have a met

28、er that measures inductance, use it to measure the inductance of the inductor coil with the iron core inside.)（选做：如果你有测量电感的仪器，可用它来测量带铁芯的电感线圈的电感系数）3.Turn on the power switch on the back of the Power Amplifier.打开功率放大器背后的电源开关。4.Click the REC button to begin collecting data. The Signal Generator will st

29、art automatically.单击记录按钮开始收集数据。信号发生器将自动开始输出信号。Data recording will end automatically after 0.02 seconds. Run #1 will appear in the Data list in the Experiment Setup window.数据记录将在0.02秒后自动结束。Run #1将出现在实验设置窗口的数据列表中。5.Turn off the power switch on the back of the Power Amplifier. 关掉功率放大器背后的电源开关。ANALYZING

30、THE DATA 分析数据The voltage across the resistor is in phase with the current. The voltage is also proportional to the current (that is, V = IR). Therefore, the behavior of the current is studied indirectly by studying the behavior of the voltage across the resistor (measured on Analog Channel B).电阻两端的电

31、压与电流同相，并且成比例（即V = IR）。因此，可以通过研究电阻两端的（模拟通道B所测）电压的行为，来间接地研究电流的行为。1.Click the Smart Cursor button in the Graph. The cursor changes to a cross-hair. Move the cursor into the display area of the Graph. 单击图表中的灵敏光标按钮。光标将变成一个十字。将光标移进图表的显示区。The Y-coordinate of the cursor/cross-hair is shown next to the Verti

32、cal Axis.光标/十字的Y坐标将显示在竖轴的旁边。The X-coordinate of the cursor/cross-hair is shown next to the Horizontal Axis. 光标/十字的X坐标将显示在横轴的旁边。2.Move the cursor/cross-hair to the top of the exponential part of the curve when the plot of voltage across the resistor (Analog Channel B) is at its maximum. Record the pe

33、ak voltage (Y-coordinate) and the time (X-coordinate) for that point in the Data section. Determine the voltage that is half of the peak (the “half-max” voltage). 将光标/十字移到曲线的指数部分的顶端，这时电阻两端（模拟通道B）的电压曲线处于最大值。将这个点的峰值电压（Y坐标）和时间（X坐标）记录在数据一节中。计算1/2峰值电压（即“1/2最大”电压）。3.Move the cursor down the exponential pa

34、rt of the plot of resistor voltage until you reach the “half-maximum” (peak) voltage. Record the X-coordinate (time) for this point.将光标沿着电阻电压曲线的指数部分向下移动，知道达到“1/2最大（峰值）”电压。记录这一点的X坐标（时间）。4.Subtract the time for the peak voltage from the time for the half-max voltage to get the time for the voltage to

35、reach half-max. Record this time in the Data Table.从1/2最大电压对应的时间中减去峰值电压对应的时间，就得出到达1/2最大电压所花费的时间。将这个时间记录在数据一节中。5.Calculate the inductive time constant based on the total resistance in the circuit and the value for the inductance of the inductor coil with the iron core: L = 18.9 millihenry or 0.0189 H. 根据电路中总的阻抗和带铁芯的电感线圈的电感系数值L = 18.9 微亨or 0.0189 H，来计算感应时间常数。NOTE: If you have a meter that measures inductance, use your measured value for the inductance of the coil plus core.注意