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University of Sharjah
Electrical and Electronics Engineering Department
0402203
Circuit Analysis I Laboratory
Experiment # 7
The Function Generator and the Oscilloscope
OBJECTIVE
To learn the fundamentals of using the function generator and the digital oscilloscope.
THEORY:
The Function Generator is a voltage source that can produce time varying voltages (waveforms).
There are four standard waveforms: sine, square, triangle and ramp (sawtooth) as shown in Figure 1.
The function generator also allows us to control the amplitude and the frequency of the waveform.
Figure 2 shows some characteristics of the waveforms: the voltage of one peak (Vp) and the peak-topeak voltage (Vp-p), which is twice of Vp for symmetric waveforms. The period (T) is also shown which
is related to the frequency as f=1/T.
Figure 2: some characteristics of the waveforms
The oscilloscope is basically a graph-displaying device - it draws a graph of an electrical signal. In
most applications the graph shows how signals change over time: the vertical (Y) axis represents
voltage and the horizontal (X) axis represents time. This simple graph can tell you many things about a
signal. Here are a few:
► You can determine the time and voltage values of a signal.
► You can calculate the frequency of an oscillating signal.
► You can see the "moving parts" of a circuit represented by the signal.
Refer to Appendix I or II for the details of the Oscilloscope you are using.
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PROCEDURE:
1. Generate a sine wave of 5 volts peak-to-peak and 1.5 kHz frequency. Display this wave on the
oscilloscope and save it on disk or draw a labeled sketch on paper. Measure the amplitude and the
frequency manually.
2. Using this sine wave as vs(t), connect the circuit shown in Figure 7 and display vs(t) and vo(t) on the
oscilloscope. Save them on disk or draw a labeled sketch on paper.
3. Repeat step 2 for a square wave of 10 volts peak-to-peak and 15 kHz. frequency.
4. Repeat step 2 for a triangular wave of 10 volts peak-to-peak and 15 kHz. frequency.
5. Connect the circuit shown in Figure 8. Generate vs(t) as a sine wave of 6 volts peak value and
1 kHz frequency. Display vs(t), vD(t) and vR(t) on the oscilloscope and save them on disk or draw a
labeled sketch on paper.
RESULTS:
1. For steps 1 to 4: plot all the waveforms recorded in the lab. State the amplitude and the frequency
for each waveform on these plots.
2. To show that the voltage divider rule is applicable for time-varying voltages:
a. Calculate vo(t)=0.6vs(t) (by VDR).
b. Plot the calculated and measured vo(t).
c. Compare the two plots.
3. To show that the KVL is applicable for time-varying voltages:
a. Calculate vD(t)= vs(t) - vR(t) (KVL).
b. Plot the calculated and measured vD(t).
c. Compare the two plots.
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