The simplest oscilloscope from a computer

It's no secret that beginning radio amateurs don't always have expensive measuring equipment at hand. For example, an oscilloscope, which even on the Chinese market, the cheapest model costs about several thousand.
Sometimes an oscilloscope is needed to repair various circuits, check amplifier distortion, adjust audio equipment, etc. Very often, a low-frequency oscilloscope is used to diagnose the operation of sensors in a car.
In this case, a simple oscilloscope made from your personal computer will help you. No, your computer will not have to be disassembled and modified in any way. All you need to do is solder the console - a divider - and connect it to the PC via the audio input. And to display the signal, install special software. In just a couple of tens of minutes you will have your own oscilloscope, which may well be suitable for analyzing signals. By the way, you can use not only a desktop PC, but also a laptop or netbook.
Of course, such an oscilloscope is hardly comparable to a real device, since it has a small frequency range, but it is a very useful thing in the household for viewing the output of an amplifier, various ripples of power supplies, etc.

Set-top box diagram


The simplest oscilloscope from a computer

Agree that the circuit is incredibly simple and does not require much time to assemble. This is a divider - a limiter that will protect your computer's sound card from dangerous voltage that you may accidentally drop into the input. The divider can be 1, 10 or 100. A variable resistor adjusts the sensitivity of the entire circuit. The set-top box is connected to the linear input of the PC sound card.

Assembling the console


You can take a battery box like I did or another plastic case.
The simplest oscilloscope from a computer

Software


The oscilloscope program will visualize the signal applied to the sound card input. I will offer you two options for downloading:
1) A simple program without installation with a Russian interface, download it.
avangard.zip [329.85 Kb] (downloads: 23364)

The simplest oscilloscope from a computer

2) And the second one with installation, you can download it - here.
The simplest oscilloscope from a computer

Which one to use is up to you. Take and install both, and then choose.
If you already have a microphone installed, then after installing and launching the program you will be able to observe the sound waves that enter the microphone. It means everything is OK.
The set-top box no longer requires any drivers.
We connect the set-top box to the linear or microphone input of the sound card and use it for good measure.
The simplest oscilloscope from a computer

If you have never had experience working with an oscilloscope in your life, then I sincerely recommend that you repeat this homemade product and work with such a virtual instrument. The experience is very valuable and interesting.

Watch a video on working with an oscilloscope for a computer


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Comments (29)
  1. feelloff
    #1 feelloff Guests 9 December 2017 15:14
    13
    Also very informative:
    1. Mukhamet
      #2 Mukhamet Guests March 28, 2018 07:46
      7
      excellent, but there is the ability to connect to a mobile phone, it would be generally good
      1. Viktor Vasilievich Chekasin
        #3 Viktor Vasilievich Chekasin Guests 27 December 2022 16:13
        0
        I heard that there is a similar program for Android. Look it up.
    2. Andrey
      #4 Andrey Guests February 1, 2019 12:53
      2
      What voltages should I connect to which connectors? How to determine the current and voltage at the connectors? There is a 1k resistor in the diagram in the article, but not in the video! How so?

      In general, I think it will do just fine for a first oscilloscope! Why not!
  2. Basil
    #5 Basil Guests 9 December 2017 15:38
    3
    Dear! there is no need to call the common wire “ground”, On your diagram there is no designation “ground” “ground” “Grounding” Yu, with respect.
  3. Sanek
    #6 Sanek Guests December 10, 2017 10:01
    12
    Very good! Already done! Thing! Where were you before)) Thank you!
  4. Paul
    #7 Paul Guests January 16, 2018 10:11
    13
    Vasily - EARTH has long been a “common wire”. So in short. There are also: “digital earth”, “analog earth”, “floating earth”. Take any bourgeois circuit and you will see GND, i.e.Ground/earth, although we are not talking about grounding. Also the same. how the concept of "digital" does not refer only to decimal digits in the form of text
  5. wonderful,
    #8 wonderful, Guests 27 March 2018 13:28
    3
    wonderful, but there is a possibility to connect it to a mobile phone, if possible, tell me
  6. Guest Mikhail
    #9 Guest Mikhail Guests 1 August 2018 19:34
    1
    Bandwidth ?
  7. Guest Alexander
    #10 Guest Alexander Guests 23 August 2018 20:00
    3
    The sound card input is shunted by two chains of unidirectionally connected diodes in series. The chains themselves are connected towards each other. Nonsense! Why is no one commenting on this “new product”?
    1. amateur
      #11 amateur Guests 26 September 2018 15:10
      12
      diodes limit the input signal to the sound card at a level of about 2.8 V, if you foolishly give 220 to the input of the set-top box. Signals of lower amplitude are not affected
      1. Vita
        #12 Vita Guests 18 July 2020 18:48
        6
        According to this scheme for switching on the diodes, everything can fall on one and it will burn out, and then... 220 no need to eat, I found the limit and made it according to another stereo scheme
    2. Dima
      #13 Dima Guests November 18, 2018 11:29
      4
      Alexander, you're a nerd.
  8. acmajor
    #14 acmajor Guests 8 February 2019 18:39
    8
    https://www.drive2.com/c/505834723478602433/ link to a similar article for the phone. There you can scale the axes with your fingers on the screen and don’t need any handles on the screen. With limiting diodes this is correct. Since there is a resistive divider in the circuit, I think it’s better to remove the variable otherwise than measure the input voltage (when adjusted with a variable, the voltage calibration is lost).
  9. Guest Evgeniy
    #15 Guest Evgeniy Guests 17 June 2019 09:10
    8
    I read and remember, but does this circuit work as a closed entrance? Let’s say I need to measure the signal level in the RS-485 interface, long distances, there is attenuation, in order to understand in which area I should install the converter to “maintain” a sufficient level.
    1. Viktor Vasilievich Chekasin
      #16 Viktor Vasilievich Chekasin Guests 27 December 2022 16:16
      1
      And place a capacitor in the gap between the potentiometer slide and the diodes.
      1. Guest Vladimir
        #17 Guest Vladimir Guests September 11, 2023 00:02
        0
        Naturally, this is a “closed” input, this is a sound card, it is impossible to measure DC voltage, no capacitor will help here, it will even make it worse, you will make the input even more “closed.”
  10. Vitalich
    #18 Vitalich Guests 4 September 2019 14:42
    3
    Can you use an integrated sound card? Judging by the video, the author of that video has a separate sound system. Just on the integrated one if you turn on the gene program. LF and feed it to the Linear input from the output and use the downloaded oscilloscope, then after 5-6 kHz it shows not a pure sine wave but some kind