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How to connect function generator software on laptop to breadboard?

  1. Jan 4, 2012 #1
    I'm using a software to generatre sine waves for my op amp circuit. I know you have to use the headphone jack to output the signal, but I don't know how I would go about connecting my headphones to my circuit. The problem is I don't know how I have to cut my headphone wire for ground and etc...
    Step by Step intstructions would be help full.
  2. jcsd
  3. Jan 4, 2012 #2


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    Science Advisor

    You probably shouldn't cut your headphone wires.

    Go to an electronics store and buy a plug like the one your headphones use and a socket to match. Also get a short length of shielded wire with two conductors. (Take your headphones and a copy of this message and show it at the store. They will know what it means.)

    Make up a cable with the plug at one end and attach the other end of the wire to your circuit. You will need to solder these connections. Plug the plug into your laptop.

    Then you should have signal voltage at your breadboard.

    Then make another cable with a socket on it at one end. Plug your headphones into this socket.
    Connect to other end of the wire to your circuit where the first wire connects.

    If you are not comfortable with soldering, you can get a ready made cable with a plug at one end and a socket at the other, and cut it in the middle.
  4. Jan 4, 2012 #3


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    Staff: Mentor

    You have found a set of broken headphones, or have bought a cheap $2 pair of ear buds to chop up, I presume? Anyone taking a plane flight seems to come back with a set of headphones or earphones, too.

    The wires inside the cable going to a pair of cheap earphones are very fragile. Snip it off near the ear buds so you are left with lots of wire to play with. Carefully open it up with a single-edge razor blade. (Preferably a used one, it won't be so likely to cut deeply when you slip. :redface: :redface: ) You should find 3 wires inside. Two will be identical, though with different coloured plastic. The earth will probably be a sparsely woven copper mesh that wraps around these two. Separate it from the others, then trim some plastic off so the exposed wires are of different lengths--a precaution that will minimize the likelihood of accidently shorting them together. (Not that it will probably harm your audio card it they do short, but no need to temp fate.)

    By salvaging a cheap plug with cable you should be able to avoid the need to do any soldering. I did say the wires are very fragile, didn't I? They are like fine pink cotton strands.

    Good luck. I hadn't before now heard of this improvised interface for home PCs. :smile:
  5. Jan 5, 2012 #4
    Thanks guys for your help
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