Simply apply Ohm’s Law to find rThevenin.. How does this RThevenin compare to the value determined in column 2. Calculate % difference between columns 2 and 4 then enter this value in Table 5-1, column 5. Table 5-1. Measured and calculated data. 1 2 3 4 5 6 7 8 % % Vab Vab % Measure Calculate Error Measured Calculated Calculated with sources 1 between 2 Thévenin (This is removed with sources measured using Ohm’s between voltage Vth) (shorted) removed and Law and measured calculated 1 Rload and and calculated 2 Part 2 Now construct the network shown in Figure 5-2, but replace Rload with a potentiometer connected between and The equivalent circuit is shown in “a” “b.” Figure 5-3. We will now determine rthevenin using the potentiometer. Measure the voltage between and as the potentiometer is adjusted. “a” “b” Adjust the potentiometer wiper until the voltmeter reads VThevenin/2 (Column 6 Table 5-1) NOT Vsource/2. The potentiometer is now set at the maximum power load which is equal to rthevenin the maximum power delivered to the load using equation (5-2). the value of the potentiometer and determine how close it is to the value of rthevenin determined in part 1, step 3. (5-2) Figure 5-3. Maximum power network. Now that this is the load for maximum power. Prove it by measuring the voltage Vab across the potentiometer after the potentiometer is rotated 1 turn CW. Then measure the potentiometer resistance at this position. Calculate the power delivered to the potentiometer using equation (5-3).
Simply apply Ohm’s Law to find rThevenin.. How does this RThevenin compare to the value determined in column 2. Calculate % difference between columns 2 and 4 then enter this value in Table 5-1, column 5. Table 5-1. Measured and calculated data. 1 2 3 4 5 6 7 8 Measured with sources removed (shorted) Calculated 1 with sources removed % between measured and Calculated 2 using Ohm’s Law and Rload % between calculated 1 and calculated 2 Vab (This is Vth) Vab % Error Thévenin voltage measured and Part 2 Now construct the network shown in Figure 5-2, but replace Rload with a potentiometer connected between “a” and “b.” The equivalent circuit is shown in Figure 5-3. We will now determine rthevenin using the potentiometer. Measure the voltage between “a” and “b” as the potentiometer is adjusted. Adjust the potentiometer wiper until the voltmeter reads VThevenin/2 (Column 6 Table 5-1) NOT Vsource/2. The potentiometer is now set at the maximum power load which is equal to rthevenin Calculate the maximum power delivered to the load using equation (5-2). Measure the value of the potentiometer and determine how close it is to the value of rthevenin determined in part 1, step 3. (5-2) Figure 5-3. Maximum power network. Now that this is the load for maximum power. Prove it by measuring the voltage Vab across the potentiometer after the potentiometer is rotated 1 turn CW. Then measure the potentiometer resistance at this position. Calculate the power delivered to the potentiometer using equation (5-3).
ECE%20109%20Laboratory%20Exercise%205.docx