Using a PC as Test Equipment

Discussion in 'General Electronics Chat' started by Wendy, Nov 1, 2013.

  1. Wendy

    Thread Starter Moderator

    Mar 24, 2008
    A plain unmodified WinPC will do a lot as test equipment with the right software. I am interested in links, which I will group in my blog, that will do various functions.

    For example, the AAC book has a link that will allow you to use the sound card as a very primitive oscilloscope. I would recommend building a buffer circuit to protect your PC, and this is not for high voltage applications. But in many cases it would be nice to see if a circuit were oscillating or clipping.


    Another interesting program I have run into is speech analyzer, which will tell you the frequency and other important information about speech. It would have other uses however.

    Note, ACC has firm restrictions on pirated or owned software, keep this in mind for your recommendations.
    #12 likes this.
  2. rogs

    Active Member

    Aug 28, 2009
    I have been pretty impressed with this freebie for audio work :

    And, IMHO, it's worth logging in (as a guest - no need to register) to get access to the V.2012 beta version, which is really excellent.

    As an audio 'scope and spectrum analyser, it's up there with some of the 'paid for' software ....again, IMHO of course!
  3. wayneh


    Sep 9, 2010
    My rig is shown here. It works well for lab bench range voltages, ie. less than 10V. The software (which was free) and computer I use are so old I won't bother detailing them.

    The point is, you can cobble together a very useful, 2-channel "oscilloscope" for almost no cost. Not useful except in the audio range, but that covers a lot of bench stuff.
  4. Mike33

    AAC Fanatic!

    Feb 4, 2005

    Wayneh, do you feel it's necessary to use actual probes? Or would shielded cable have a reasonable response? Say, run cable to old meter probes... I'd like to set something like this up, too (have an old 766MHz PC, ha ha), and have messed around with Analyser. Only interested in AF...

    How about an input buffer? Unknown what my sound card impedance is (ESS Allegro). Thought about doing a dedicated divider (x10) followed by a buffer, just to ensure the safety of the card if I hit it with something over 5V. I'm assuming DC will be blocked (but can add an output cap if that's advisable)...
  5. t06afre

    AAC Fanatic!

    May 11, 2009
    I once build an AC skin conductance meter using PC and a sound card
  6. wayneh


    Sep 9, 2010
    No, my "probes" are just little alligator clips on the other end of that coax cable. I think there might be shielding up to the point where the probes break out into separate wires. I do not think the last few inches of those individual wires are shielded.
  7. Mike33

    AAC Fanatic!

    Feb 4, 2005
    Thanks, we'll give it a try! I know the accuracy will be suspect due to stray capacitance working with resistance to filter etc., but this might work "well enough"...just to see clipping and for making comparisons and so on.
  8. studiot

    AAC Fanatic!

    Nov 9, 2007
    My cardex seems to have got lost around 2000 on this subject, but I'm sure there was also a Wireless World series on this.

    E = Elektor
    Map = Maplin magazine
    ETI = Electronics today International
    EPE = Evereday and Practical Electonics
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    This one is a free, small and very simple PC based signal generator;

    for audio frequencies. At higher frequencies 12-20kHz the sine output shape from the PC sound card is not great, as the sound card is driven with samples at 44.1kHz (and 20kHz gives only 2.2 samples per cycle).

    But for a free fast download it's a working PC based audio signal generator, with no hardware needed (as it uses the PC's internal sound card).
  10. Mike33

    AAC Fanatic!

    Feb 4, 2005
    This one will do quite a bit as a function generator, too. Killer sweeps, 2 tones at once, etc:

    I made the leap and got a Tektronix 60MHz scope on Ebay last night. $90 delivered, which seems to be a good price for that generation. For what I do, I will likely never need anything over 1MHz! There are quite a few on there worth checking out if you are going to take the hobby to 'the next level'...
  11. Danm1


    Jul 19, 2010