Small current sources are frequently used in many electronic circuits and integrated circuits; however, they are rarely used in industrial power circuits. They are also commonly used to drive light emitting diodes (LEDs). The maximum power theorem states that the maximum power will be delivered to a load when the load resistance is equal to the This is the basis for selecting the Thévenin resistance. resistance of a speaker system for a stereo. This assures that in the design stereo systems that maximize the power will be delivered from the amplifier to the speakers. PROCEDURE Part 1 Measure the resistor values R1, R2, and R3 the myDAQ multimeter. Figure 5-2. Do not use the color code to determine the resistance value. Choose three resistors that are reasonably close in value. Do not pick, for example, 10K, 300, and 100 ohms. You should realize by now that the resistor color codes are not an accurate way to determine resistor values. Construct the circuit shown in Figure 5-2 on the protoboard. Using a multimeter, measure the voltage between points and with NO LOAD connected. Record your “a” “b” measurement in column 6. This is VThevenin by definition. Remove the 10 Vdc power source and connect a jumper between and This is “1” “2.” the same as shorting the supply voltage mathematically. Now measure the resistance between and using your multimeter. By definition this is RThevenin. Record this “a” “b” value in Table 5-1. Column 1. Calculate RThevenin by combining the series and parallel resistors with the source disabled (shorted). Record this value in Table 5-1. Column 2. Now compare your measured value and calculated values in order to perform an error analysis. Enter this value in column 3. Figure 5-2. Linear resistor network. We are now going to determine RThevenin in another way. Connect a load to the circuit as shown in Figure 5-1. For best results the load resistance should be in the same range as your estimated RThevenin. Now measure the output voltage between and in order to make the appropriate “a” “b” calculation. Divide this voltage by Rload. This will be the current going through the Thévenin equivalent circuit.
Small current sources are frequently used in many electronic circuits and integrated circuits; however, they are rarely used in industrial power circuits. They are also commonly used to drive light emitting diodes (LEDs). The maximum power theorem states that the maximum power will be delivered to a load when the load resistance is equal to the Thévenin resistance. This is the basis for selecting the resistance of a speaker system for a stereo. This assures that in the design stereo systems that maximize the power will be delivered from the amplifier to the speakers. PROCEDURE Part 1 Measure the resistor values R1, R2, and R3 the myDAQ multimeter. Figure 5-2. Do not use the color code to determine the resistance value. Choose three resistors that are reasonably close in value. Do not pick, for example, 10K, 300, and 100 ohms. You should realize by now that the resistor color codes are not an accurate way to determine resistor values. Construct the circuit shown in Figure 5-2 on the protoboard. Using a multimeter, measure the voltage between points “a” and “b” with NO LOAD connected. Record your measurement in column 6. This is VThevenin by definition. Remove the 10 Vdc power source and connect a jumper between “1” and “2.” This is the same as shorting the supply voltage mathematically. Now measure the resistance between “a” and “b” using your multimeter. By definition this is RThevenin. Record this value in Table 5-1. Column 1. Calculate RThevenin by combining the series and parallel resistors with the source disabled (shorted). Record this value in Table 5-1. Column 2. Now compare your measured value and calculated values in order to perform an error analysis. Enter this value in column 3. Figure 5-2. Linear resistor network. We are now going to determine RThevenin in another way. Connect a load to the circuit as shown in Figure 5-1. For best results the load resistance should be in the same range as your estimated RThevenin. Now measure the output voltage between “a” and “b” in order to make the appropriate calculation. Divide this voltage by Rload. This will be the current going through the Thévenin equivalent circuit.
ECE%20109%20Laboratory%20Exercise%205.docx