Download EECE 206 Lab 2: Basic Electrical Measurements

EECE 206
Page 1 of 8
Lab 2: Basic Electrical Measurements
Laboratory Goals





Familiarize students with digital multimeters and the desktop power supply
Calculate voltage and current values for two circuits
Construct simple resistive series and series-parallel circuits
Measure the resistance, current, and voltage of resistive circuits
Record results in the laboratory notebook
Pre-lab reading


Basic resistive networks, EECE 203 textbook
Student Reference Manual for Electronic Instrumentation Laboratories
Equipment needed






Lab notebook, pen
DC power supply (located at your assigned desktop station)
Tektronix DM 501 Digital Multimeter (located at your assigned workstation)
Fluke 8050A Digital Multimeter (located in your assigned equipment cabinet)
3 test leads, red, with banana/EZ Hook ends (located in your assigned equipment
cabinet)
3 test leads, black, with banana/EZ Hook ends (located in your assigned
equipment cabinet)
Parts needed







Circuit breadboard
Lab parts kit
Resistor, 470 Ohms, ¼ W
Resistor, 560 Ohms, ¼ W
Resistor, 1.5k Ohms, ¼ W
Resistor, 2.2k Ohms, ¼ W
Brown jumper wires, 3 (U-shaped wires, found in the parts kit)
Lab safety concerns



Do not turn on the power supply until you have rechecked your circuit for correct
wiring
Do not allow the test leads connected to the power supply to touch each other
Note that current and voltage measurements require different connections to the
multimeter (details in section 2 below)
EECE 206
Page 2 of 8
Lab 2: Basic Electrical Measurements
1. Pre-Lab Design Calculations

Calculate IR1, VR1, and VR2 for Circuit 1 below:
Circuit 1

Next, Calculate IR1, IR2, IR3, VR1, VR2, VR3, and VR4 for Circuit 2 below:
Circuit 2


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
Copy the calculated values for circuits 1 and 2 into the tables
EECE 206
Page 3 of 8
Lab 2: Basic Electrical Measurements
2. Circuit 1 Construction and Test Measurements

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.
R1
R3
J1
J2
R2
J3
R4
Circuits 1 and 2




Turn on the TM 504 (i.e., pull the white switch on the right side of the box)
Locate the Tektronix DM 501A Digital Multimeter (contained within the TM504
box)
Press the brown k button which selects the resistance measurement mode
Press the white 20k button which selects the resistance range
EECE 206
Page 4 of 8

Lab 2: Basic Electrical Measurements
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

Briefly clip the two test leads together (the multimeter reads approximately 0.000
Ohms)

Remove the jumper wire (J1) from between R1 and R3
Remove the jumper wire (J3) from between R3 and R4
Clip the red test lead to either of the legs of resistor R1
Clip the black test lead to the other leg of R1
Record the resistance value shown on the multimeter in your lab notebook
Unclip the two test leads from R1 and repeat the measurement for the other 3
resistors
Unclip the two test leads from the last resistor measured, and set them aside
briefly






EECE 206
Page 5 of 8








Lab 2: Basic Electrical Measurements
Press the DC button in the VOLTS section of the multimeter for voltage
measurements
Check to see that the 20 volt range button is pushed in (the same button used to
select 20k for the resistance measurements)
Locate the Systron-Donner power supply at your station
Turn on the power supply (the red power light comes on)
Turn the METER SELECT knob to the VOLTS setting
Turn the black V ADJ knob for power supply B until the B meter shows
approximately 10V
Turn the power supply off
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


Clip the red test lead from the Tektronix multimeter to the left leg of R1 (i.e., +V)
Clip the black test lead from the Tektronix multimeter to the bottom leg of R2
(i.e., ground)
EECE 206
Page 6 of 8



Lab 2: Basic Electrical Measurements
Connect the third pair of test leads to the Fluke 8050A digital multimeter and to
the circuit as shown below:
Press the white mA button and the green 20 button to select the 20mA range
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
EECE 206
Page 7 of 8









Lab 2: Basic Electrical Measurements
Turn on the Fluke multimeter
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)
Turn the black FINE knob for power supply B until the Tektronix multimeter
reads approximately 10V
Record the current IR1, as measured by the Fluke multimeter
Unclip the (Tektronix’s) black test lead from the bottom leg of R2 and clip it to
the right leg of R1
Record the voltage drop VR1, as measured by the Tektronix multimeter
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)
After all the measurements are recorded, turn off the power supply
Unclip both Tektronix multimeter test leads from the circuit
3. Circuit 2 Construction and Test Measurements


















Connect jumper wire (J3) between R3 and R4 (this completes the path to ground
for the branch circuit containing R3 and R4)
Turn on the power supply
Record the current IR1 with the Fluke multimeter, and voltage measurements
VR1, VR2, VR3, VR4 with the Tektronix multimeter
Turn off the power supply
Remove jumper wire (J3) from between R3 and R4
Unclip the Fluke multimeter test leads from R1 and R2, and clip them to R3 and
R4 respectively for current measurement
Connect the jumper wire (J1) between resistors R1 and R2
Turn on the power supply
Record the current IR3 with the Fluke multimeter
Turn off the power supply
Remove jumper wire (J2) from between R3 and R2
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
Replace jumper wire (J3)
Turn on the power supply
Record the current IR2
After all the measurements are recorded, turn off the power supply
Turn off both multimeters
Unclip all test leads from the circuit
EECE 206
Page 8 of 8
Lab 2: Basic Electrical Measurements
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.