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Signal generator

Discussion in 'The Projects Forum' started by Gdrumm, Apr 22, 2009.

  1. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    I ordered a really cheap kit on line (from Hong Kong), and when it arrived, it needed to be wired. The input jack plug is a 3 lead type, 1 red, 1 white, and 1 ground bundle. I have 2 Alligator Clips, 1 red, and 1 black. I'm not sure how to wire it up.

    I'm guessing that the ground wires and the white wire go together, with the black clip, then the red plug wire goes with the red clip.

    Does that sound right?

    Last edited: Apr 22, 2009
  2. StayatHomeElectronics

    AAC Fanatic!

    Sep 25, 2008
    If they did not give you documentation on the kit then can you follow the wires from the connectors to the first components, maybe a voltage regulator?

    The last kit I ordered came with no instructions in the kit but there were drawings and schematics on the web for them. Try that as well...

    S@H Electronics
  3. Audioguru


    Dec 20, 2007
    Please say what the plug is for.

    It is a stereo plug. Red and white are left and right channels and the copper wire is the common. Shorting the white wire to ground or to the common might blow up something.
  4. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    I believe it plugs into a laptop; doesn't seem like Audio, although that could certainly produce a wave form.

    It appears to be the two leads coming from an Oscilloscope (a software / PC oscilloscope).

    I ordered it thinking I could learn a little bit about O-scopes, and circuits.

    Where would the ground wire go then? Just leave it unconnected? CLip it?

    If it's DC, then it's + and -, and I would suppose red with red will do.

  5. SgtWookie


    Jul 17, 2007
    This cheap kit will quickly wind up roasting your sound card in your laptop/computer if you try to hook it up, and it may very well destroy more than just the sound card when things go awry.

    You've been scammed, I'm afraid.

    The components are only worth about a dollar or so even if you'd bought them from Radio Shack. If you attempt to use them for the purpose they sold them to you for, you could do many times that investment in damage.

    Here's a link to a hardware buffer schematic that will at least provide a modicum of protection for a PC sound card:

    You could still easily roast your computer using it, but it's far better than what you have now.
  6. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    Thanks Sarge, I just consider this a lesson learned.

  7. zero_coke

    Active Member

    Apr 22, 2009
    Everything is made in China anyway, so I there is absolutely no arguement about this thing made there and something made here.
  8. Wendy


    Mar 24, 2008
    I'll let you two Canadians argue that one out.

    Actually, I don't see anything wrong with using the computer speaker out as a function generator, as long as you build a buffer, such as an op amp.

    If you're going to that much trouble though, I'd build one from the ground up. I've been working on one off and on for long before I got here, I'll finish it up eventually and put it in the projects collection forum.