ENGINEERING-12L
Oscilloscope Measurements Exercise
Experiment 8A
Lab Logistics
Experimenter(s):
Date:
Part-1 Directions
1. Check out one each of
 DMM
 TEK TDS210 oscilloscope
 Instek Function/Signal Generator (SG)
2. Turn on SG and press 1k, sinewave buttons (see Fig1), then adjust frequency dial to 1
Figure 1 • Instek Function (Signal) Generator Control Panel
Connect the SG-Output to the Scope-Input by clipping red-red leads and black-black leads
 [SG MAIN Output connection]→[Scope CH1 Input Connection]
3. Turn on the Scope. This should produce a sinewave trace as in Figure 2.
 If the trace does NOT resemble Figure 2, then press the AUTOSET button on the scope one
time. If this does not yield the desired trace then see the instructor.
 The AUTOSET button may be used at anytime to return to a “BaseLine” trace.
4. Examine the scope display. It shows a graph of voltage verses time [v(t) vs t] on a grid that is 8Squares high by 10 squares wide. Notice along the bottom of the grid that scope displays scaling
information for the squares.
 The vertical Ch1 scale shown on the bottom left indicates how many Volts/square
 The horizontal scale shown on the bottom middle shows how many μs/square
(250 μs per square = 250x10-6 SEC/DIV)
Figure 2 Scope Connection showing sinewave from Signal Generator
5. PLAY WITH THE SCOPE KNOBS
 Make sure the scope display shows CH 1 in the upper right corner. See Figure 2.
 This enables the vertical and horizontal controls for the Channel-1 scope trace.
 Adjust the large VOLTS/DIV and SEC/DIV knobs indicated to obtain the largest
i. Sinewave Vertical Deflection (Squares Up & Down)
ii. Horizontal spread for one cycle (Squares Side-to-Side)
 Move the trace up/down, left/right to an advantageous measurement position using the small
POSITION knobs under VERTICAL and HORIZONTAL panels.
 Trace should look similar to 2 only with less cycles, just 1 period of the waveform.
6. Measure Vpp by counting the number of vertical divisions between the bottom of the signal-trace
and the top of the trace. On old scopes this was called the Vertical Deflection of the “Cathode Ray”
(electron beam) that drew the trace
 Calculate Vpp by multiplying: Vpp = [no. vert. div]•[VOLTS/DIV]
7. Measure the Signal period, T, by counting the number of horizontal divisions between either:
 Adjacent peaks
 Adjacent troughs
 Adjacent zero-crossing points
 Calculate T by multiplying: T = [no. hori. div]•[SEC/DIV]
 Then the Frequency, f = 1/T
Table I – Scope Measurements
SG
FREQUENCY
Dial Position
SG Amplitude
Dial Position
1.
0.4 kHz
20%
2.
1.0
30%
3.
1.5
60%
4.
2.0
80%
5.
5.0
100%
No.
Time
Base
t/div
Period,
T
Frequency
Voltage
Scale
V/div
Vpp
Voltage
ENGINEERING-12L
RL and RC Step Response
Experiment-8B
Lab Logistics
Experimenter(s):
Date:
Part-1 Directions
8. Check out one each of
 DMM
 TEK TDS210 oscilloscope
 Instek Function/Signal Generator (SG)
9. Build the Inductor circuit schematic on your breadboard.
10. Connect the Scope Ch1 across the 100 Ohm resistor, and Ch2 across the Signal
Generator.
11. Turn on and set the SG, then turn on the Scope. Adjust the SG AMPL/FREQ to get 5Vpp,
500Hz SQUARE WAVE
12. Adjust the scope settings so you see one period of the input signal square wave
13. Measure the Time Constant on the Ch1 signal by projecting the tangent of the decay curve
to its intersection on the time axis, as shown in the next figure.
14. Complete the table below of Time constant calculation and measurement. Calculate the
time constand by using the formula Tau = L / R (L in Henrys, R in Ohms) but realize
that the signal generator has a 50 Ohm internal resistance that should be added first to R.
Table II – Scope Measurements for 33 mH Inductor Circuit. After finishing with 100 Ohm,
try swapping with 330 and 470 Ohm resistors.
No.
Nominal
Resistor
6.
100 Ohm
7.
330
8.
470
Effective
R
(measured
+ 50 Ohm)
SG
Frequency
Time
Base
t/div
Measured Calculated
Tau
Tau
% Err
15. Now Build the Capacitor circuit shown:
16. Complete the table below of Time constant calculation and measurement. Calculate the
time constand by using the formula Tau = R*C (C in Farads, R in Ohms) but realize
that the signal generator has a 50 Ohm internal resistance that should be added first to R.
Table II – Scope Measurements for 0.1 uF Capacitor Circuit. After finishing with 0.1 uF
try swapping with 1 uF and 10 uF Capacitors.
No.
Capacitor
9.
0.1 uF
10.
1 uF
11.
10 uF
Effective
R
(1K
measured
+ 50 Ohm)
SG
Frequency
Time
Base
t/div
Measured Calculated
Tau
Tau
% Err