MEASURING DIGITAL SIGNALS WITH
MULTI-METER AND OSCILLOSCOPE
LAB 2 REPORT
SEMESTER 1, 2023/2024
FACULTY
: ENGINEERING FACULTY
COURSE CODE
: KS21501
COURSE NAME
: LABORATORY II
TUTOR
: JAMAL AHMAD DARGHAM
NO. MATRICS NUMBER
NAME
1
BK22110157
MOHD HAIQAL ALIFF BIN MHD SHUKIRI
2
BK22110186
MOHAMMAD NADHIR BIN ABDUL MANAF
3
BK22110167
NUR MUHAMMAD FIRDAUS @ FEREDERIC
JUNIOR PHILIP
4
BK22110184
JACKSON CHEE ZHENG CHENG
OBJECTIVE
- To measure digital signals using an oscilloscope and multimeter.
INTRODUCTION
Digital signals are essential to modern electronics for many operations, such as data
processing, transmission, control systems, and digital communication. Accurate
measurement and analysis of digital signals are essential for comprehending their
characteristics and ensuring their operation in a wide range of electronic devices and
systems. This lab exercise specifically aims to familiarise students with the
fundamental tools and techniques used for measuring digital signals using an
oscilloscope and a multimeter.
A multimeter is a vital instrument for engineers and technicians of all experience levels
as it measures a variety of electrical characteristics, such as voltage, current,
resistance, and continuity. In this experiment, we will examine its application in
measuring digital signals by keeping an eye on voltage levels and voltage transitions.
An oscilloscope, on the other hand, is a specialised instrument designed to see and
analyse signals that vary over time. It provides thorough information about the
waveform shape, timing, amplitude, and frequency of signals. Oscilloscopes may be
used to analyse digital waveforms in addition to analogue signals, which is how they
are most commonly utilised. In this experiment, we will use an oscilloscope to view
digital signals and analyse their characteristics, such as signal integrity and rise and
fall timings.
This experiment gives students practical experience with the essential measuring
instruments and lays the foundation for a deeper understanding of digital electronics
and the critical role that accurate measurements play in designing and troubleshooting
digital systems. Furthermore, the knowledge gained from this experiment may be
useful in a wide range of fields, including digital logic design, embedded systems,
microcontroller programming, and telecommunications.
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PROCEDURE
Before starting the experiment, we set up the multimeter by first inserting the test
leads—the black lead first, then the red lead—into the jacks. In that order, the red
and black test leads were inserted into the COM and V jacks, respectively.
Nevertheless, once the leads were eliminated, this order was altered.
EXPERIMENT 1 : MEASURING RESISTANCE
1.
Firstly, a resistor was borrowed from the lab assistant, and it was photographed
for this report (refer to Figure 1).
2.
The resistor's resistance value was figured out in the first stage by looking at
its colour bands and utilising a resistance chart as a reference. The resistance
of the resistor was then recorded in Table.
3.
For the second stage, the resistance of the resistor was measured with a
multimeter. There was absolutely no electricity supplied to the circuit.
4.
The circuit was examined to ensure it was free of any capacitors before a
resistance reading was taken. After that, the meter's dial was set to read an
ohmmeter.
5.
The resistance was measured by moving the multimeter's probe over the
resistor to make sure there was excellent contact between the test leads and
resistor. The resistance value was recorded in Table 1's "Measured (W)"
column.
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EXPERIMENT 2 : MEASURING VOLTAGE AND CURRENT
1.
Firstly, we were given a breadboard, which we used to construct a circuit with
a 1k resistor and an LED.
2.
Next, a 5V DC power source was used to power the circuit. Following that, an
image of the circuit was captured and labelled as Figure 2.
3.
The multimeter's dial was then set to the voltmeter setting after that. The
voltage across the resistor was measured by putting the probe across it at the
point where the black lead was connected first, followed by the red lead. A
photo that shows the connection and the multimeter measurement that was
made is Figure 4.
4.
The voltage across resistor measurements are listed in Table 2. The voltage
across the LED was then measured by placing the probe across the resistor. A
photo that shows the connection and the multimeter measurement that was
made is Figure 5.
5.
The voltage across LED values are shown in Table 2. Next, the current flow via
the LED was measured in Figure 3. To do this, the multimeter dial was switched
on and adjusted to read as an ammeter, putting it in the appropriate range.
6.
After the circuit was opened, the probe was inserted into the open circuit. The
recorded current flow reading is displayed in Table 2.
EXPERIMENT 3a : CALIBRATE OSCILLOSCOPE PROBE
1.
For this experiment, the lecture gave us this link to a training video:
https://youtu.be/u4zyptPLlJI?si=RYEOYq_ptzOLIOPZ
2.
After watching the video, we calibrated our oscilloscope using its guide.
Figure 6 in this study shows a snapshot of the single cycle wave form of the
calibrated probe.
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EXPERIMENT 3b : MEASURING THE FREQUENCY
1.
For the last experiment, we were then given a signal generator to produce a
sinewave at a frequency of 10 kHz.
2.
A single-cycle sinewave's frequency was found using the calibrated
oscilloscope.
3.
In the end, a picture of the exhibited waveform was captured and will be
shown as Figures 7.a and 7.b in this report.
RESULT
EXPERIMENT 1 : MEASURING RESISTANCE
Figure 1 : 1KΩ value of the resistor
Colour band
Theoretical (Ω)
Measured (Ω)
Error (Ω)
Brown, Black, Red
1000
1046
4.40
Table 1 : Resistance Measured Using Multimeter
4
EXPERIMENT 2 : MEASURING VOLTAGE AND CURRENT
Figure 2 : The arrangement of the resistor and LED in the circuit.
Figure 3 : The measurement of current through the LED.
5
Figure 4 : The reading of voltage across the resistor.
Figure 5 : The reading of voltage across the LED.
6
Component
Voltage (V)
Current (mA)
Resistor
3.03
-
LED
1.92
0.31
Table 2 : Voltage and current measured the in the circuit
EXPERIMENT 3a : CALIBRATE OSCILLOSCOPE PROBE
Figure 6 shown the single cycle wave at the oscilloscope.
Figure 6 : The single wave form of the calibrated probe.
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EXPERIMENT 3b : MEASURING THE FREQUENCY
Figure 7.a shows the signal generator set up to produce a frequency of around 10
kHz, and Figure 7.b shows the single-cycle sinewave that the calibrated oscilloscope
produced.
Figure 7.a : Signal Generator display frequency around 10kHz
Figure 7.b : Single Cycle Generated on Calibrated Oscilloscope
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DISCUSSION
A multimeter was used in Experiment 1 to measure the resistance of a resistor, and
the results were entered into Table 1. When the observed and calculated resistance
values were compared, a 4.40 ohm error was found. This highlights the need of
precisely measuring resistance as even minute inaccuracies might affect how well
electrical circuits function.
In the second experiment, an LED and a resistor were subjected to voltage and current
measurements. Table 2 contains the voltage and current values, which are important
information for comprehending how certain parts behave in a circuit. It is crucial to
remember that appropriate safety measures should be followed while measuring
voltage and current to protect both the researcher and the apparatus.
The oscilloscope probe's calibration was described in full in Experiment 3a, and the
report contained a picture of the calibrated probe's single cycle waveform. To get
precise measurements and guarantee the oscilloscope readings are reliable,
calibrating the oscilloscope probe is essential.
Experiment 3b, the last one, employed the calibrated oscilloscope to determine the
frequency of a sine wave. The single-cycle sine wave produced by the calibrated
oscilloscope and the signal generator setup are depicted in the figures. It is crucial to
follow the right methods while using oscilloscopes and signal generators to prevent
breaking the equipment and getting readings that are off.
All things considered, the lab report does a good job of illustrating how multimeters
and oscilloscopes are used in real-world situations to measure digital signals. A
greater grasp of digital electronics and the significance of precise measurements in
electronic systems is made possible by the comprehensive figures and tables, which
clearly illustrate the measurements that were made. It is crucial to remember that,
in order to avoid mishaps and equipment damage, safety procedures should always
be followed when handling electrical equipment.
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