How Oscilloscope Works

what is an oscilloscope used for

An oscilloscope is a device for displaying varying voltage signals graphically, usually in the form of a calibrated diagram of multiple signals. After the waveform is displayed, its properties such as amplitude, frequency and so on can be analyzed. It uses the time-domain method of displaying changes in electrical signals that have passed through it. They are commonly known by different names, including CRO and DSO, which have evolved from measuring voltage changes over time based on events.

An oscilloscope is an essential lab instrument. This instrument is used for measuring voltage, current, frequency, and power. In this blog post we will discuss how oscilloscopes work and what they are used for today.

What is an oscilloscope?

How Oscilloscope Works

In school you probably made charts, and you probably saw them in the newspaper as well. These graphs often illustrate how the value of a quantity over time varies, such as a heart rate, the price of stock, or a nation’s exchange rate. Y-axis represents the quantity plotted vertically, and x-axis represents the period plotted horizontally. If you didn’t have an oscilloscope, you may find that charts like this take a long time to plot. You can feed oscilloscope signals from probes attached to electronic circuits, scientific instruments, or medical monitors to draw charts automatically.

What can we use oscilloscopes for?

It is possible to use an oscilloscope for observing signals in all sorts of ways. In electronics courses, oscilloscopes will be used to monitor the changes in circuit signals over time. They can also be used to troubleshoot TVs, radios, and much more. Coaxial cables are used to connect the probes of a typical oscilloscope to electric currents, but this does not mean oscilloscopes can only measure electricity. You can use an oscilloscope to measure almost anything when you attach a transducer (that converts one type of energy into another). Among the various types of transducers that can be used to study sound signals with an oscilloscope are microphones (which convert sound energy to an electrical signal), thermocouples (which measure temperature changes), or piezoelectric transducers (which generate electricity when squeezed).

What makes oscilloscopes so useful is their ability to visualize and comprehend invisible signals. Ultrasound is above human hearing threshold, so by definition, it cannot be heard by humans. However, if you use an oscilloscope, you can see it easily and study it. The oscilloscope, on the other hand, offers the possibility of seeing and studying sounds in a way that may not otherwise be possible for those with hearing impairments.

How an oscilloscope works

Despite their innumerable similarities, oscilloscopes are almost exactly the same as traditional televisions. Often, oscilloscopes are referred to as cathode-ray oscilloscopes. The back of a TV screen is coated with phosphors that make electron beams scan across it back and forth. The phosphors illuminate when the beam strikes the screen. Electron beams sweep across the screen in less than a blink of an eye and build up the picture you see. Afterwards, it’s the same thing all over again. Once more. Once more. so, Instead of seeing a still picture, you see a moving one.  Oscilloscopes work in much the same way except that the electron beams draw graphs rather than pictures. What you are really seeing when you look at a line on an oscilloscope screen is the wobble of an electron beam!

One thing to keep in mind is that, what appears on your on-screen chart depends on the signals transfer into the x and y connections. Traditional oscilloscopes are analog devices because they correspond one to one with these two things. Alternatively, we could say that the trace on the screen is an analogy of your object of study.

Types of oscilloscopes


Cathode-ray tubes (CRT) were used to create oscilloscopes, as we already learned. Its bulk, weight, power usage, unreliability, and cost make it an unattractive investment. The CRT television has been increasingly replaced by LCD technology, which is more convenient. So, CRT oscilloscopes are almost all being replaced with flat-panel LCD screens. As opposed to older oscilloscopes, LCD oscilloscopes draw traces through digital electronics instead of moving electron beams — effectively mimicking what happens when using the older technology. It is generally cheaper and more compact to use LCD oscilloscopes.

The traditional oscilloscope makes use of entirely analog technology. You can feed them signals, and they will display them on the screen in accordance with what you input. The LCD oscilloscope is usually a digital oscilloscope. Analog signals are converted into digital form by analog-to-digital converters, then the numbers are plotted on the screen.

Plugin (USB) oscilloscopes

Computers, tablets, and smartphones already come with CRT or LCD displays, so buying the best usb oscilloscope is no longer necessary for occasional hobby uses. Many companies sell affordable oscilloscopes for mobile devices that plug into USB ports or have equivalent leads. You can use a PC or mobile device as an oscilloscope if you have one of these programs. It’s great to have that option!

How Oscilloscope Works

Analog oscilloscope

Let’s take a look at how analog oscilloscopes work. Here is a block diagram that shows the process easily. Let’s have a look at the diagram and read the full description to know how analog oscilloscope works:

how oscilloscope works

Analog oscilloscope block diagram


Your circuit under test is connected to this piece. Oscilloscope measures the difference between two points (voltage) with probes that typically have two tips each.


It is often necessary to amplify (increase in amplitude) or attenuate (decrease in amplitude) an electrical signal before it can be sensibly displayed to the user or without damaging the oscilloscope’s inner circuitry.

Trigger System:

Triggers determine when the oscilloscope begins displaying waveforms based on a user-defined condition (such as a voltage threshold). It can be extremely useful when finding intermittent pulses in a circuit or when synchronizing the display to regular patterns like sine waves so that the pattern remains steady on screen.

Sweep Generator:

Sweep generators create sawtooth voltage patterns in order to control the horizontal plates in CRTs. With this technique, the beam of light moves from one side of the CRT to the other. The  sweep generator can be set to produce a certain frequency and triggering.

Horizontal Amplifier:

The horizontal amplifier, which can control the horizontal plates in the CRT, is much like what was found after the probe. It enhances the sawtooth wave from the sweep generator to control the amplitude of the horizontal plates.


A phosphor-coated screen is illuminated by an electron gun that continuously fires electrons onto it. The beam is deflected by two sets of plates. Using the probe voltage, the vertical plating is controlled directly, and using the sweep generator, the horizontal plating is controlled. A solid line is shown on the screen when the beam rapidly deflects. As the probe voltage varies over time, this line on the display shows it.

Digital Oscilloscope

In the 1980s, Nicolet manufactured the digital oscilloscope (DSO) by utilizing a relatively slow  analog-to-digital converter (ADC). Digital oscilloscopes have become faster, smaller, and more popular as digital technology has advanced.

Digital Signal Processors are essentially sophisticated computers fitted with high-end analog to digital converters. Although there are many similar functions and features to those found on older analog oscilloscopes, there are also some that are new.

Let’s have a look at the diagram and read the full description to know how Digital Oscilloscope works:

how oscilloscope works

Digital Storage Oscilloscope Block Diagram


In order to test your circuit you need an oscilloscope that can measure the voltage between two points. The tips of most probes are attached to different nodes on your circuit.


In oscilloscopes, electrical signals are amplified or attenuated by circuits. This will allow for an effective display and will prevent damage to internal components.

Trigger Select:

Most oscilloscopes can display waveforms triggered by either an internal or external signal (from another source).

Control Logic:

An opportunity for a user to adjust signal capture and display logic. Analog oscilloscopes have horizontal controls that are analogous to the controls on the control panel, but they offer more options.


A sampling rate is determined by the control logic of the analog-to-digital converter. Binary numbers are created from these samples and then stored in memory.


In memory, sampled signals are represented by digital data. Using this information, a graph representing a close approximation of the original electric signal can be generated.

Time Base:

The horizontal axis on the display is controlled by the time base as set by the control logic. The  user can adjust the time base based on a single trigger point to capture sporadic signals or to hold periodic signals, such as sine waves, steady on the display during a period.


An oscilloscope displays waveforms on a screen by combining memories with time bases and displaying waveforms from memory. Waveform in which voltage and time are represented as Y-axis and X-axis, respectively, often represents the sampled signal. In older DSOs, CRT displays are used as displays, but most modern DSOs use LCDs.

The Evolution of Oscilloscopes

The oscilloscope has evolved into a smarter, more powerful piece of test equipment since their invention. PC-based oscilloscopes are highly portable and analyze and display waveforms with the processing power of a computer. A digital phosphor oscilloscope (DPO) can display a signal’s frequency-of-occurrence in a manner that mimics an analog oscilloscope.

Logic analyzers specialize in displaying digital signals, which are made possible by oscilloscopes. The mixed signals oscilloscope (MSO) is the result of combining these two powerful instruments. Analog signals can be displayed on MSOs just like oscilloscopes, while digital signals can be analyzed like logic analyzers.


What is the working principle of oscilloscope?

Voltage can be measured with an oscilloscope. During this process, a small current is drawn in order to measure the voltage drop across a resistor. Using an electric field, the voltage drop amplifies and deflects the electron beam either in the X (horizontal) or Y (vertical) axis.

What is the purpose of an oscilloscope?

With an oscilloscope (or scope), voltage signals are tested and represented as waveforms. Graphs are used to show the change in signals.

What are the major components of oscilloscope?

Oscilloscopes have three main parts – the horizontal system, the vertical system, and the trigger system. The oscilloscope is able to reconstruct signals accurately based on the contribution each system makes. Oscilloscopes have three distinct front panels branded  Vertical, Horizontal, and Trigger.

Is an oscilloscope necessary?

It is true that oscilloscopes are primarily used for measuring electrical waveforms. Furthermore, it also has a pretty high degree of accuracy for measuring mostly constant voltage levels. Moreover, it can detect small fluctuations in battery power, which is not possible with most multimeters.

Why are oscilloscopes so expensive?

The oscilloscope is a precision instrument. To ensure they meet standards, they must undergo strict quality control. As a result, costs continue to rise. In addition, higher bandwidth means higher costs.


It only took a few decades for the oscilloscope to evolve from its early days as an analog instrument that could do very little more than display voltage and frequency, into a sophisticated device with PC-based capabilities. These modern devices can process waveforms at speeds of up to 300MHz, which is much higher than any analog scope ever created.

There are even digital phosphor oscilloscopes (DPOs) on the market today that mimic the appearance of their predecessors but have all of this power behind them. If you want to learn more about how these instruments work or what types exist, let us know!

Siglent Vs Rigol

siglent vs rigol

Siglent and Rigol are staple choices of brands when looking for a premium oscilloscope that won’t disappoint. They both create almost similar devices with good learning curves, a broad spectrum of applications, high precision measurements, automatic and manual operation modes, HD screen resolutions, and many more.

However, when choosing, you may only need to part with some dime for a single device. As such, it becomes a bit daunting to know which brand wins in the tussle of Siglent vs. Rigol oscilloscopes. In this comparison, we’re going to cover all the features that set each brand apart, similarities, and differences.

In case you’re in a hurry, you can jump onto the conclusion part of this article for a glimpse of our preferred choice. We also show the metrics we’ve considered to come up with the verdict.

Siglent Vs. Rigol Brief Analysis

Siglent and Rigol oscilloscopes share myriads of similarities. If you’re a beginner in the circuitry industry, it is normal to confuse which brand to choose. For decades, those who’ve been in the industry cannot differentiate and select the best model between the two.

To be pragmatic, every Siglent model has an equal Rigol competitor. Only a few design tweaks can weigh out, but the two will almost be the same on functionality. So expect this competition to be a stiff one with a lot to take into account.

To understand the two brands, it is best to consider their originalities and a brief history. Well, Siglent is a European brand founded in 2002. This company has developed over the past one and half decades to become a renowned electronic creator that also makes DC power supplies, multimeters, and waveform generators.

Siglent has branches and outlets across the globe. It is the top producer of oscilloscopes in China and the Asian world as a whole. Almost 15% of the brand’s annual revenues go into R&D technology support programs. Siglent products are among the topmost creative devices you’ll ever find in the market, so is the SDS1202X oscilloscope.

Rigol, on the other hand, is a Chinese brand founded in 1998. The company has its headquarter in Beijing, China, and several branches and outlets across the globe. This brand also manufactures waveform generators, spectrum analyzers, RF signal generators, multimeters, and oscilloscopes.

Rigol is one of the electronic device producers that are always on the trend for new and more advanced creations. The brand currently has more than 493 patents. It prides on developing the RSA5000 real-time logic analyzer and a wide range of top-notch oscilloscopes, including the Rigol DS1054Z.

Siglent Vs Rigol Comparison Chart

Siglent SDS1202XRigol DS1054Z
200Mhz bandwidth and two channels50Mhz bandwidth and four channels
7-inch 800×480 resolution screen display7-inch 800×480 resolution screen display
14 Mpts Irecord Wave Depth12 Mpts Irecord depth that expands to 24 Mpts
1 gsa/use Real-time sampling rate1 gsa/use sampling rate
16.53 pounds weight6.60 pounds weight
One USB port for CableOne USB port for cable
Electric cordedElectric corded

Siglent Vs. Rigol (side By side comparison of their features)

Siglent SDC1202X-E200

This oscilloscope comes in a rectangular body with two stands attached at the base for support. The outer surface is finished in a grey shade that gives it the appeal it deserves. The brand has used a dark-colored hue for the screen that enables the oscillating waveforms to show effortlessly, even in the dark.

Just below the screen are menu buttons and the ON-Off power button. The farthest left, below the screen, is also a USB port for connecting the device to any electronic device you’d wish to test voltages on.

The right side of the oscilloscope features navigation buttons that you can use to initiate, run, and fluctuate triggers. The top part contains controls for selecting and adjusting intensities, clearing sweeps, saving and recalling sweeps, displaying measurement, modifying cursors, printing results, and a lot more. You can as well run or auto-stop the triggers using the two buttons at the farthest top-right corner.

The middle buttons are for variables and math functions. You can use them to adjust the depth of your waveform either vertically or horizontally. The trigger buttons at the middle, farthest right, applies whenever you want to set up either single or double channels when triggering.

At the bottom-right side are three ports for X, Y inputs, and an extension. You can use these ports to connect the device to the grid.


Rigol DS1054Z is a rectangular-shaped oscilloscope that features a grey color for the body. It comes with two stands at the base to augment its bench-top body style. The screen is striking dark to allow for easy peaking of the waves as they form.

Unlike the Siglent counterpart, this oscilloscope comes with its Primary menu buttons located at the farthest left, lining vertically. Below the six buttons are the ON-OFF button and a USB port for connecting a secondary device. The screen below is an empty groove that serves as a cherry top to its design tweaks.

The navigation buttons line on the right side, with the top part featuring clear, auto, run/stop, and single-channel tabs. The middle-right buttons for REF and Math functions and 4 CH buttons for running advanced algorithms: the Menu, Mode, and Force buttons line to the farthest right on the middle right.

Lastly, at the bottom of the navigation buttons are four CH ports for plugging CH and power cables. Each port has a description of the cable it accepts to eliminate any confusion when using.

  • Number of Channels

The competition of Siglent Vs. Rigol cannot be complete without mentioning the number of channels each has. Well, Siglent SDS1202X-E200 comes with two channels, with a button that you can use to initiate and run only one channel.

Rigol SD1054Z, on the other hand, comes with four channels, with a button that you can use to run only a single track. For higher scopes of functions or use on multiple devices, this model is your go-to.

  • Screen Display

Siglent  SDS1202X-E comes with a large-7 inch screen display that is sizable enough to capture two waveforms. The TFT-LCD display uses the ultra-high-definition 800 x 480 resolution. It is bright enough for use even in the dark.

Similarly, Rigol DS1054Z features a 7-inch screen display that supports four waveforms simultaneously. It leverages the 800 x 480 screen resolution so that you can be sure of an oscilloscope bright enough for use anytime.

  • Bandwidth

Siglent SDS1202X-E has a bandwidth of 200Mhz. It is one of the few oscilloscopes in the medium category that will guarantee you a detailed measurement. Even more, it supports the 1gsa/use sampling rate, making it very accurate and ideal for all tasks that require precision measurements.

Rigol DS1054Z, on the other hand, has a bandwidth of 50Mhz. The bandwidth and the channels are analog. As such, it is not better placed to guarantee accurate results in precision measurements.

  • Boot-Time

If you’ve ever used devices from both Siglent and Rigol, you’ll concur that Rigol devices boot faster than their Siglent counterparts. On average, Rigol’s advanced devices boot in less than 10 seconds, while Siglent’s take up to 30 seconds to start.

However, how fast your device will boot primarily depends on its period of use and the state of its inner components. But even with that, you will never go wrong with the Rigol DS1054Z if boot time is one of your critical concerns.

  • Price

Siglent SDS1202X comes with a $379 on Amazon. You’ll also need to pay shipping fees and import charges. Nevertheless, this price tag is susceptible to fluctuation. So it can go higher or lower over a certain period.

Rigol DS1054Z features a $349 price tag on Amazon. Additionally, you have to spend on shipping costs that vary depending on your country. If you intend to cut the cost corners, this model will warm your heart as it is less expensive.

Siglent Vs Rigol (Pros and cons)

Siglent SDS1202X


  • It has a generous bandwidth for precision measurements
  • It has a memory depth of 14MPts for a detailed display
  • It has a high-resolution 7-inch screen display
  • Ideal for use with all functions that require double channel
  • It comes with 1FFT math analysis for running advanced logics
  • It comes with a storage memory bus for playbacks


  • A bit pricier compared to most variants in the market
  • Not ideal for functions that require multiple channeling

Rigol DS1054Z


  • It comes with up to four channels for various uses
  • Can focus and zoom a specific part of the waveform
  • It comes with a 12MPT memory depth that you can upgrade to 24MPT
  • The ultra-display 7-inch screen is sizable enough for use with up to 4 channels


  • The four channels are analog
  • The 50MHz analog bandwidth doesn’t suit precision measurement

The Winner

Rigol DS1054 warms the heart for its number of channels; However, its bandwidth is lower than its main competitor. But even with that, its price is a steal when you factor in the scope of functions it can undertake; we have no choice short of crowning it the winner in the tight race of Siglent Vs. Rigol

How to Connect an Oscilloscope to a Circuit

how to connect an oscilloscope

Oscilloscopes may seem like daunting devices at first, but try not to let the several knobs and buttons intimidate you.

They are extremely useful in the field of electrical studies and tasks concerning electronics.
When connected to a circuit, a USB oscilloscope graphs out the electrical current running through the circuit onto a screen, and they also provide users with the core information needed to work out a lot of other elements such as amplitude, transient signals, statistics, etc.

This article will be walking you through the process of how to connect an oscilloscope to a circuit so that you can get the information you need.

Circuits and Oscilloscopes

A circuit is essentially a gapless path along which a circulating electric current flows. This path is made up of electrical components such as resistors, capacitors, wires, inductors, loads (such as a bulb), sources (such as batteries), etc.

When a circuit is connected to an oscilloscope, the behavior of the current flowing through the circuit is visualized on the oscilloscope’s screen, which can then be observed, analyzed, and used in the form of information for further calculations and measurements.

The oscilloscope presents the voltage of the circuit as a waveform graph, with time (in seconds, milliseconds, microseconds, or nanoseconds) displayed on the horizontal axis and voltage displayed on the vertical axis of the graph.

Calibrating Your Oscilloscope before Connecting It to the Circuit

Before you connect your oscilloscope to your circuit, you will need to prepare the former so that it works properly with your specific circuit’s signal. This is called ‘calibrating’ the oscilloscope.

Depending on the oscilloscope, you can measure as low as a few millivolts to as high as a few hundred volts of voltage, and similarly, you can visualize pulses of both very short durations and of very long durations.


In order to properly see how your circuit’s voltages are changing, you need to scale the voltage and time axes accordingly.

The display of the oscilloscope looks like a simple graph with variable scales for the horizontal and vertical axes.


You need to estimate how high and low your peaks and troughs will go and make sure you set the volts/division and time/division knobs appropriately. Ensure that both the maximum and minimum voltages would be visible on the screen at the same time.


Adjust the horizontal scale so that it fits a few periods (that is, the time required by a wave to complete one cycle).

After connecting the circuit, adjust the scale as necessary. The oscilloscope helps to visually test the circuit, so scale it accordingly so that you can see exactly what configuration you need.

Connecting an Oscilloscope to a Circuit

There is very little that goes into the task of connecting a circuit and an oscilloscope. However, this task may seem difficult in the beginning. The following steps should help you walk through the process easily.

First, connect the probe’s ground clip to the circuit’s ground plane. Next, connect the probe tip to the circuit’s signal output port.

Once these two steps are completed, you should be able to see a line appear on the oscilloscope’s screen. This line is known as the waveform of your signal (that is, of the circuit).

This waveform can help you find out not just the voltage of your circuit, but also the frequency, amplifier gain, current, mean, standard deviation, etc.


Learning to operate any new device is a matter of trial and error. However, when working with electronics, it is essential that you keep yourself safe and also conduct necessary and extensive research before performing a new task using your device.

Hence, follow the steps mentioned above when connecting your oscilloscope to a circuit in order to do it properly and safely.

And if you come across any problems while doing the process, give us a shout in the comments or mail us. We’ll try to provide an appropriate solution to your problem in a short time.