Introduction to the Oscilloscope – What is an Oscilloscope and How to use it?

Ever seen this device but do not know what is it? Well, it’s an

Oscilloscope! (O-scope for short)

The Oscilloscope is an important tool in any electrical engineer workbench. No matter if you are a beginner or professional engineer, you would require this tool.

If you want something more advanced that can provide you with more information than your multimeter to troubleshoot your circuit, the Oscilloscope is a must-have!

Without further ado, let us jump right into it to find out more about the Oscilloscope.

Today, we will be covering:

  • What is a Oscilloscope?
    • Basic Oscilloscope Functions
    • What can O-Scopes Measure?
    • When should you use an Oscilloscope?
  • Types of Oscilloscope
    • Which Oscilloscope should I pick?
  • How to use an Oscilloscope?

Suggested Readings

Before continuing with this article, you should be familiar with the concepts below. Check out the following articles if you want to learn more!

What is an Oscilloscope?

An oscilloscope is a type of electronic test instrument that can graphically display signal voltage changes. Other signals (such as sound or vibration) can be converted to voltages and displayed on the screen of the oscilloscope.

Engineers use oscilloscopes to study the changing process of various electrical phenomena for laboratory work. It can be used to capture, process, display and analyze the waveform and bandwidth of electronic signals.

They graph an electrical signal as it varies over time and produces a 2D graph with the x-axis being time and y-axis being voltage.

Basic Oscilloscope Functions

  • Displays and calculate the frequency and amplitude of an oscillating signal on a graph.
  • Displays the voltage and time of a particular signal.
  • Troubleshoot any possible malfunction components of your project by looking at the expected output of a particular component. (See whether a malfunctioning component is distorting the signal
  • Show how much of a signal is direct current (DC) or alternating current (AC).

If you look at an Oscilloscope, there will be controls surrounding the scope’s screen. They can be used to adjust the scale of the graph (vertically and horizontally) which lets you zoom in and out on a signal. There are also trigger controls for you to stabilize and display a repetitive waveform

What can O-Scopes Measure?

Mainly used to measure volts, the Oscilloscope can measure a variety of other signals from:

  • Current
    • To measure current, you can either measure the voltage drop across a shunt resistor or use a current probe.
  • Sound
    • To measure sound, use a transducer that converts the audio signal to a voltage.
  • Frequency and Period
    • Frequency = Number of times per second a waveform repeats
    • Period = Number of seconds each repeating waveform takes.
  • Duty Cycle
    • Ratio of how long a signal is positive VS negative each period.
  • Rise and fall timing
    • Measure the duration where signals rise to a high point and the duration where signals fall to a low point.
    • Useful if you wish to find out how fast a circuit can respond to signals
  • Voltages characteristics
    • Measure the magnitude (amplitude) of a signal (Peak-to-peak amplitude)
    • Maximum and Minimum Voltages (Calculate the highest and lowest voltage of your signal)
    • Mean and Average Voltages
  • Resistance
  • DC Voltage / AC Voltage

When should you use an Oscilloscope?

Here are some scenarios where the Oscilloscope will be useful during troubleshooting and research situations:

  • Finding the FREQUENCY and AMPLITUDE of a signal. (Important if you are trying to debug a circuit). Using the O-scope, you can find out whether a certain component in your circuit has malfunctioned.
  • Finding out how much noise is in your circuit.
  • Identifying the shape of a wave (Square, Sawtooth, Step, Pulse, Sine).
  • Quantifying phase differences between two different signals.

Types of Oscilloscope

There are mainly 2 types of O-scopes – analog and digital. The main difference is that analog O-scopes uses continuous variable voltages and use an electron beam to directly map the input voltage to the display while digital O-scopes sample the input signal with an analog-to-digital converter and map that reading to the display.

Analog scopes are often older, have lower bandwidth and fewer features, thus, we will not be talking much about them.

Digital Scopes

Under the category of digital scopes, they are further split into more categories:

  • Digital Storage Oscilloscope (DSO): Has memory to store waveforms and display them for a period of time.
  • Digital Phosphor oscilloscopes (DPO): Uses a parallel processing architecture to enable it to capture and display signals.
  • Digital sampling oscilloscopes: Used for analysing high-frequency signals for example up to 50 GHz.

Which Oscilloscope should I pick?

Well with so many types of Oscilloscopes to pick from with various features and performance, it can be hard to pick one for yourself.

The answer is simple, pick the one that suits your project needs the most! For example, small lightweight handheld digital oscilloscopes are perfect for you if you want something portable and easy to bring around.

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MiniDSO DS213 Nano 4 Channel 100MSa/s.

Personally, I prefer DSOs like the one shown above as they provide storage where you can store, capture, display and print waveforms whenever you want. Not to mention, this DSO shown above, is only 99.5mm x 58.5mm, making it very portable and can even fit in your pocket!

Good news for you too if you wish to get this miniDSO as we are having a 20% OFF for this product! Just apply the code: TOOLS20 to enjoy the discount.

Looking for another type of Oscilloscope like a USB DSCope? We have it too! Check out this DSCope U3P100 Dual-Channel 1GSa/s Sampling/100Mhz Bandwidth USB3.0 – Portable Oscilloscope!

The DSCope U3P100 oscilloscope is an ultra-portable, dual-channel, USB-based digital oscilloscope, with powerful performance (100MHz bandwidth, 1GSa/s sample rate, 2M real-time and 256M single record length). With the easy-to-use cross-platform software, DSView, your circuits can be debugged and analyzed using your desired operating system. Also, with its compact size, you can observe the analog wave and its frequency spectrum conveniently, anywhere at any time. This is an ultra-portable oscilloscope that can easily fit in your pocket and carry around. Also, it’s outer case is made of CNC Aluminum for protection and features a fanless design without noise.

How to use an Oscilloscope?

Lastly, after learning about the Oscilloscope functions, measurements, and types, how do you actually use an Oscilloscope?

Step 1: Turn on the Oscilloscope

  • Firstly, you will, of course, have to turn on the Oscilloscope before anything else. To do this, just press the switch which is often labeled as “Power” or “Line”.
  • If nothing is plugged into the Oscilloscope, you should see a flat line on your display. (this means that the voltage of the input is not changing over time”
  • During this step, remember to connect your probes to the scope as well.

Step 2: Connect to an Oscillating Signal

  • For this step, you will need a steady signal of constant frequency.
    • Most scopes will already have a built-in frequency generator for that to emit a reliable set-frequency wave. (Set it to a pulse or square wave with 2.5V amplitude at 500Hz)
    • If you do not have a waveform generator, you can upload a code to an Arduino to generate a signal.

Step 3: Trigger

  • Once you connect to the signal via your probes, you should start seeing a signal begin to dance on your screen.
  • By moving the horizontal and vertical system knobs, you can maneuver the waveform around the screen. (If you rotate the scale knobs clockwise, it will zoom into your waveform and if you rotate it anti-clockwise, it will zoom out.)
  • Now, if your wave on the display is unstable, rotate the trigger level dial. When doing this, you will see a trigger level indicator move up and down the display.
  • Take note that if the trigger is higher than the tallest peak of your waveform, the signal will become unstable.

Step 4: Start measuring!

  • Now you are ready to start measuring with your O-scope! To get you started, I will go through with you guys how to measure amplitude.
  • Before we begin, what is amplitude? The amplitude of the wave is the difference between the height of the peaks of a wave and the wave’s equilibrium.
  • To measure amplitude, for example, the distance between the equilibrium line and the peak of the wave is 3.5 vertical grid divisions, with volts/div at 1V, 3.5 vertical grid divisions = amplitude of wave is 3.5V.
Video on Measuring Average Voltage by Using DSO Nano v3


That’s all for today guide on the Introduction to the Oscilloscope – What is an Oscilloscope and How to use it. I hope you found this guide useful!

If you have any questions on the Oscilloscope, just drop them down in the comments section down below!

Looking for Oscilloscopes? Seeed has tons of them! Check them out here

Additional Resources

What is an Oscilloscope? – Functions and Tutorial

[Wiki] DSO Nano v3


March 2020