Experiment 6 - Thevenin Equivalent Circuits and Power Transfer | ECE 103, Study notes of Electrical and Electronics Engineering

Download Experiment 6 - Thevenin Equivalent Circuits and Power Transfer | ECE 103 and more Study notes Electrical and Electronics Engineering in PDF only on Docsity! ECE103. Spring 12 Experiment #6 Student name(s): Page 1 of 5 03/09/12 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 about matching loads to maximize power transfer. * Equipment list : 1. MB Board and components 2. Multimeter 3. Xplorer handset 4. Resistors various values between 100Ω and 5 kΩ. I.) Thevenin Equivalent (85 points): Construct the circuit shown in figure 1. Use R1=R4= 10 kΩ and R2=R3=1kΩ. Various values of resistance will be used for Rload. To connect the different loads use the multipurpose socket in the component’s board. In this experiment, we will consider the Thevenin equivalent for the circuit composed of R1, R2, R4, R5 and the 9V source. Rload is the load and is not part of the circuit to be replaced with a Thevenin equivalent circuit. By the way, this configuration is called a bridge circuit. Install a 100Ω resistor for Rload, then measure the voltage between the points a and b and measure the current Iload which passes through Rload. To perform these measurements use the Xplore handset unit. • How should the amp meter be connected? • How should the voltmeter be connected? ECE103. Spring 12 Experiment #6 Student name(s): Page 2 of 5 03/09/12 Change the value of Rload and complete the table below. Note that RLoad = ∞ Ω is accomplished by leaving an open circuit between point a and b. The current through the infinite load resistance will be 0 mA as already entered for you in the table. For the case of Rload = 0Ω, put a wire between points a and b for a short circuit. In this case, the voltage between a and b will be 0 V as shown in the table. Table(1) Rload (Ω) Iload (mA) Vab (volts) infinite (open circuit = OC) 0 VOC: 0 (short circuit = SC) ISC : 0 Using MATLAB plot the data from the table above on a graph of Vab (y-axis) vs. Iload (x-axis) for all values of Rload and attach the plot to this report. What type of curve fits the data? What is the slope of the plot (include the right units)? ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………… Now disconnect Rload and the power supply from your circuit. Replace the branch of the circuit that had contained the power supply, Vs, with a short circuit. Using the ohm meter measure the resistance between the points a and b. R(ab) =…………………………….. How does this value of resistance compare numerically to the slope of the plot in step 5? ……………………………………………………………………………………………………… ……………………………………………………………………… Now try to decide how to select values for the components of the Thevenin equivalent circuit shown in Figure 1, so that the equivalent circuit will produce the same effect as the original circuit. That is, the two circuits should produce the same values of Vab and Iload for any of the given load resistors. Think about this problem for a few minutes before continuing.