function generator output current??

Discussion in 'The Projects Forum' started by EEDude, Feb 22, 2011.

  1. EEDude

    Thread Starter Active Member

    Nov 18, 2008
    Im trying to use a function generator to drive a magnet. I can't find any current specs on any that I have seen. Will a function generator on it's own without an amplifier output enough current to drive the magnet? The magnet resistance is about 1.5 ohms and I am looking for current up to about 3A.
  2. SgtWookie


    Jul 17, 2007
    No, typical function generators aren't designed to output that much power.

    You'll need an amplifier.
  3. someonesdad

    Senior Member

    Jul 7, 2009
    Here's a way you can answer such a question yourself. The function generator's output current will be determined by the output impedance and the output voltage. Measure the maximum output voltage; call this V0. Set the output to a relatively small value; say half a volt or so; call this V. Connect a variable resistor to the output along with a voltage measuring device suitable for the frequency. Change the resistor until the output is V/2. Measure the resistance R of the resistor; this is the (real) part of the output impedance. Most function generators have output impedances of about 50 ohms.

    Then the maximum output current you can expect is V0/R.
  4. EEDude

    Thread Starter Active Member

    Nov 18, 2008
    OK got it thanks! I am going to be trying to use a Kepco BOP 20-10M power supply as an amplifier. The documentation is not very good and I am a little lost on how to set it up.

    One question is what type of cable would be best to use from the output of the function generator to the pin connectors of the power supply amplifier inputs?
  5. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    Why not just use DC with the magnet? Why do you need a function generator?
  6. EEDude

    Thread Starter Active Member

    Nov 18, 2008
    dc is too slow, the magnet is being driven to 3K Oe