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Sound Card Oscilloscope Software

Sound Card Oscilloscope Probe Software

The articles about sound card oscilloscopes have been so popular that I've written a whole book about it. The book shows you exactly how you can build the scope into a nice enclosure so that you can conveniently use it on all of your projects.

I've included a project which adds two additional features that allow you to generate signal waveforms using the headphone output and to calibrate the scope so that you make absolute amplitude measurements. I also cover two very capable and yet free-to-use software applications that can be used with it. The book is available now in kindle format from here: Sound Card Oscilloscope - Build Better Electronic Projects

The sound card oscilloscope probe that you can build from the article How To Make A Free Sound Card PC Oscilloscope is great for examining waveforms from around 20Hz to 15kHz and it has a lot of potential especially if you don't have the use of a full blown commercial oscilloscope. The software that I used in the article is called Winscope and does a pretty good job but I did notice one or two not so good points with it so I went looking for alternatives. I found one that I am very pleased with on first sight and I wanted to tell you about it here.

Winscope had two small problems. The first one is that you can't expand the widow to dedicate your entire screen to the oscilloscope. At least I couldn't find a way to do it. This isn't a big problem but it would be a nice to have feature. Also the traces offered by Winscope were a little ragged around the edges. Again not a big problem but I had hoped for something a little better.

Soundcard Oscilloscope by Christian Zeitnitz

I came across the Soundcard Oscilloscope which is free for private and non commercial use and decided to try it out. I was pleasantly surprised. I found that not only could the scope window be resized to full screen but the displayed signals seem to be much cleaner and stable. I tried it out on my multivibrator and you can see the results below.

Scope traces from multivibrator at 1khz

The image above shows the Soundcard Oscilloscope displaying signals from the collector and base of one transistor of a multivibrator circuit running at approximately 1kHz.

Scope traces from multivibrator at 12khz

The image above shows the Soundcard Oscilloscope displaying signals from the collector and base of one transistor of a multivibrator circuit running at approximately 12kHz.

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Comments (8)

Topic: Sound Card Oscilloscope Software
Full StarFull StarFull StarFull StarHalf Star 4.5/5 (3)
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can i use this for repair of two way radios like CB's for example? either on laptop or minitowers or towers??
8th March 2020 4:14pm
mike (Spain) says...
I have this running on Win 8.1 but it works only for about 1 second when I put a signal on the I/P and then it drops to a straight line.
17th February 2015 10:50am
Steve (UK) says...
Hi Mike,

I've just tried it on my Windows 8.1 PC and it appears to be fine. Make sure that the Run/Stop button is green and the Amplitude knob is turned anti-clockwise to increase the gain. Also remember that the sound card scope cannot display DC.

Hope this helps.
17th February 2015 12:33pm
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Mughees (Pakistan) says...
Hello Steve,
I am facing a problem. I am applying the dc to scope but it only displays noise instead of showing a straight dc line !!! plz help me in resolving this
24th December 2014 10:32am
Steve (UK) says...
Hi Mughees, There could be a number of reasons for your problem. First of all the PC sound card is AC coupled so it is not possible to display a DC level. This doesn't sound like your problem however. Have you tried applying an ac signal to the scope? If you have and all you get is noise then there is either a wiring problem with your probe or the mic input has not been selected as audio input on your PC. This is assuming that your sound card is ok of course. You should check this by trying ... Read More
24th December 2014 6:33pm
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Marut (India) says...
Steve I need help.

Suppose I am directly giving the input to the soundcard without the protection circuit, what is the maximum voltage that I can allow to pass without blowing up my soundcard?

Specifically, would voltages less than 9V range be safe to pass directly?
9th August 2014 2:56pm
Steve (UK) says...
Hi Marut, The simple answer is do not apply peak to peak voltages of more than 1V. The long answer is more complicated. The microphone input is designed to work with signals of only 10mV. If you have a line input or a dual line/microphone input then the specification is usually 100mV. So to be fully certain of not damaging your sound card without knowing exactly what the specification of your card is, you should stick with signals with amplitude less than this. Most signals that you work with ... Read More
10th August 2014 3:16pm
Marut (India) says...
Thank you so much Steve. Precisely what I wanted...
11th August 2014 6:41pm

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