Download ECE 211 Electrical Circuits Lab I

ECE 213 Electrical Circuits Lab I
LAB #1
Spring 2017
Name ___________________
Section ______________
The Measurement Lab
OBJECTIVE:
To become familiar with the Oscilloscope, function generator, digital multimeter and sinusoidal
measurements.
COMPONENTS AND EQUIPMENT:
1. Oscilloscope
2. Function Generator
3. Digital Multimeter (DMM)
BACKGROUND:
During labs this semester the voltage sources will be sinusoidal. This requires learning new equipment
for producing and measuring the sinusoidal voltages that will be seen in the circuits. In this lab the
oscilloscope, function generator and digital multimeter will be introduced. To understand sinusoidal
voltages, such as the following, the ways magnitude can be represented will need to be explained.
v  Vm cos(t   ) Volts
In the above the voltage magnitude is represented as Vm which is the peak voltage, Vp. The voltage can
be represented as the peak-to-peak voltage Vpp which is twice the peak voltage Vp. The voltage
magnitude can also be represented as the root-mean-square (RMS) which is the peak voltage Vp divided
by the square root of two. These relationships can be seen in the following equation.
V pp
2
 V p  2Vrms
For measuring voltages oscilloscopes can measure peak or peak-to-peak voltages. Digital multimeters
when using AC voltage selection will measure RMS voltage.
In engineering for any circuit the calculated and measured value need to be compared. The way it is
compared is using a percent error. To compute the percent error the following equation will be used,
which will be used throughout the semester.
PercentError 
MeasuredValue  CalculatedValue
100%
CalculatedValue
ECE 213 Electrical Circuits Lab I
LAB #1
Spring 2017
PROCEDURE:
In this lab data will be measurement of a function generator using an oscilloscope and digital
multimeter (DMM). Follow the procedure below and answer question asked.
1. Write down the hardware you are using.
2. Turn on Oscilloscope.
3. Turn on function generator and set to a sinusoid with a peak value of 2.5 volts and
frequency of 1000 Hz.
4. Connect the function generator to the Oscilloscope.
5. Set the time/division of 500µs.
6. Adjust the voltage/division to the largest it can be while still viewing the whole
waveform. Adjusting the reference location to also maximize this value.
7. Using cursors measure the maximum and minimum voltage of the waveform. Record this
value in the Voltage Measurement Table.
8. Using the DMM measure the voltage on the terminals of the function generator.
9. Perform Calculations in Voltage Measurement Table.
10. Using the vertical cursors measure the period of the waveform. Record in the Period
Measurement Table.
11. Calculate frequency.
12. Change the time/div of 200µs. Observe the change of the wave. How many divisions
long is the wave from peak to peak? _____________
13. What is the frequency? _______________
ECE 213 Electrical Circuits Lab I
LAB #1
Spring 2017
Voltage Measurement Table:
Cursor A Reading: (V)
Cursor B Reading: (V)
A-B (Peak to Peak reading): (V)
DMM Reading (V) – This is rms reading
Calculated peak to peak value from DMM (V)
PercentError 
OSCOPE  DMM
100%
DMM
Note: DMM reading needs to be peak-to-peak value
Period Measurement Table:
Time Cursor A: (s)
Time Cursor B: (s)
A-B: (s)
Calculated Frequency: (Hz)
Recall: f 
1
T
Frequency indicated from function generator:
(Hz)
Percent Error
QUESTIONS:
ECE 213 Electrical Circuits Lab I
LAB #1
Spring 2017
1. What is the maximum RMS voltage the function generator can output? (This will require maxing
out the voltage of the function generator and measure with DMM).
2. What can you tell about the percent error for voltage and frequency?
3. What are the differences between DMM and Oscilloscope measurements?
WRITE CONCLUSION:
Write a paragraph concluding on the lab. It should include information about results and if they
are what was expected. This would be comparing calculated and measured values. It should
give a qualitative analysis of the lab.