EECE 206 Lab 2: Basic Electrical Measurements
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Laboratory Goals
q Familiarize students with digital multimeters and the desktop power supply
q Calculate voltage and current values for two circuits
q Construct simple resistive series and series-parallel circuits
q Measure the resistance, current, and voltage of resistive circuits
q Record results in the laboratory notebook
Pre-lab reading
q Basic resistive networks, EECE 203 textbook
q Student Reference Manual for Electronic Instrumentation Laboratories
Equipment needed
q Lab notebook, pen
q DC power supply (located at your assigned desktop station)
q Tektronix DM 501 Digital Multimeter (located at your assigned workstation)
q Fluke 8050A Digital Multimeter (located in your assigned equipment cabinet)
q 3 test leads, red, with banana/EZ Hook ends (located in your assigned equipment cabinet)
q 3 test leads, black, with banana/EZ Hook ends (located in your assigned equipment cabinet)
Parts needed
q Circuit breadboard
q Lab parts kit
q Resistor, 470 Ohms, ¼ W
q Resistor, 560 Ohms, ¼ W
q Resistor, 1.5k Ohms, ¼ W
q Resistor, 2.2k Ohms, ¼ W
q Brown jumper wires, 3 (U-shaped wires, found in the parts kit)
Lab safety concerns
q Do not turn on the power supply until you have rechecked your circuit for correct wiring
q Do not allow the test leads connected to the power supply to touch each other
q Note that current and voltage measurements require different connections to the multimeter (details in section 2 below)
1. Pre-Lab Design Calculations
q Calculate IR1, VR1, and VR2 for Circuit 1 below:
Circuit 1
q Next, Calculate IR1, IR2, IR3, VR1, VR2, VR3, and VR4 for Circuit 2 below:
Circuit 2
q Create two tables in your lab notebook, with the headings shown below. (Be sure to make two columns under each resistance, current or voltage – one for the calculated value, and the other for measured values)
Circuit #1 Vin R1 R2 IR1 VR1 VR2
Circuit #2 Vin R1 R2 R3 R4 IR1 IR2 IR3 VR1 VR2 VR3 VR4
q Copy the calculated values for circuits 1 and 2 into the tables
2. Circuit 1 Construction and Test Measurements
q Build the circuit exactly as shown below (bend the brown jumper wires as shown; these wires are later removed for resistance and current measurements). Resistors are found in the resistor cabinet.
Circuits 1 and 2
q Turn on the TM 504 (i.e., pull the white switch on the right side of the box)
q Locate the Tektronix DM 501A Digital Multimeter (contained within the TM504 box)
q Press the brown kW button which selects the resistance measurement mode
q Press the white 20kW button which selects the resistance range
q Connect a pair of red and black test leads to the multimeter as shown below for resistance measurements:
Tektronix DM 501A Digital Multimeter set for Resistance Measurements
q Briefly clip the two test leads together (the multimeter reads approximately 0.000 Ohms)
q Remove the jumper wire (J1) from between R1 and R3
q Remove the jumper wire (J3) from between R3 and R4
q Clip the red test lead to either of the legs of resistor R1
q Clip the black test lead to the other leg of R1
q Record the resistance value shown on the multimeter in your lab notebook
q Unclip the two test leads from R1 and repeat the measurement for the other 3 resistors
q Unclip the two test leads from the last resistor measured, and set them aside briefly
q Press the DC button in the VOLTS section of the multimeter for voltage measurements
q Check to see that the 20 volt range button is pushed in (the same button used to select 20k for the resistance measurements)
q Locate the Systron-Donner power supply at your station
q Turn on the power supply (the red power light comes on)
q Turn the METER SELECT knob to the VOLTS setting
q Turn the black V ADJ knob for power supply B until the B meter shows approximately 10V
q Turn the power supply off
q Connect the second pair of red and black test leads between the power supply and the circuit as shown below:
Systron-Donner Power Supply and Circuit Power Connections
q Clip the red test lead from the Tektronix multimeter to the left leg of R1 (i.e., +V)
q Clip the black test lead from the Tektronix multimeter to the bottom leg of R2 (i.e., ground)
q Connect the third pair of test leads to the Fluke 8050A digital multimeter and to the circuit as shown below:
q Press the white mA button and the green 20 button to select the 20mA range
q Check to see that the white DC button is out for DC current measurements
Fluke 8050A Digital Multimeter set to Measure Current
Fluke 8050A Multimeter connected to the Circuit for Current Measurement
q Turn on the Fluke multimeter
q Turn on the power supply (notice the Fluke’s display now shows the current through R1 and R2, and the Tektronix multimeter shows the input voltage)
q Turn the black FINE knob for power supply B until the Tektronix multimeter reads approximately 10V
q Record the current IR1, as measured by the Fluke multimeter
q Unclip the (Tektronix’s) black test lead from the bottom leg of R2 and clip it to the right leg of R1
q Record the voltage drop VR1, as measured by the Tektronix multimeter
q Unclip both Tektronix multimeter test leads from R1 and repeat the voltage measurement for R2 (the black test lead again goes to the bottom leg or R2)
q After all the measurements are recorded, turn off the power supply
q Unclip both Tektronix multimeter test leads from the circuit
3. Circuit 2 Construction and Test Measurements
q Connect jumper wire (J3) between R3 and R4 (this completes the path to ground for the branch circuit containing R3 and R4)
q Turn on the power supply
q Record the current IR1 with the Fluke multimeter, and voltage measurements VR1, VR2, VR3, VR4 with the Tektronix multimeter
q Turn off the power supply
q Remove jumper wire (J3) from between R3 and R4
q Unclip the Fluke multimeter test leads from R1 and R2, and clip them to R3 and R4 respectively for current measurement
q Connect the jumper wire (J1) between resistors R1 and R2
q Turn on the power supply
q Record the current IR3 with the Fluke multimeter
q Turn off the power supply
q Remove jumper wire (J2) from between R3 and R2
q Unclip the Fluke multimeter test leads from R3 and R4, in clip them to the left leg of R3 and the top leg of R2 respectively
q Replace jumper wire (J3)
q Turn on the power supply
q Record the current IR2
q After all the measurements are recorded, turn off the power supply
q Turn off both multimeters
q Unclip all test leads from the circuit
4. Analysis
Write a summary report for this lab. Be sure to also include the following topics:
Compare theoretical vs. measured values. Are there differences? If so, Why?
Explain any difficulties you had with this lab. (Please include suggestions to improve the lab, if you have them).
Clean up
Before leaving the lab, take a few minutes to make sure all equipment and test leads are returned to your cabinet, and then lock it. Return the cabinet key to your T.A. Pick up any loose parts on the workstation table, and wipe off any eraser shavings, or other debris with a paper towel. Dispose of the paper towel and debris in the wastebasket.