Female jack negative or positive outter casing?

Discussion in 'General Electronics Chat' started by bearhugstoyou, Jan 8, 2013.

  1. bearhugstoyou

    Thread Starter New Member

    Jan 8, 2013
    I'm fixing a transformer feed for an electronic music foot pedal electronic device.
    I'm working on the supply end to the female output.
    Which is the negative of the female jack and the positive? Inner? Outter? is negative?
    One of those 9 V feeds to a foot pedal device for music.

    A 1st timer on this ! So excuse an concise detail rambling. ;)
  2. paulktreg

    AAC Fanatic!

    Jun 2, 2008
    It could be wired either way round. I would say however that outer negative is most common. You sometimes find a small picture next to the socket showing polarity?
  3. JMac3108

    Active Member

    Aug 16, 2010
    Watch out - they come in both varieties: center positive and center negative.
  4. wmodavis

    Well-Known Member

    Oct 23, 2010
    To tell which way is correct for your device wire it up based on your best guess then plug it in and if it burns up you made the wrong guess. Next time wire it the other way.
  5. BillB3857

    AAC Fanatic!

    Feb 28, 2009
    Open the device the power supply is for and find the filter caps. Negative lead of the cap will go to the negative terminal of the connector. Check with an ohm meter.
  6. tubeguy

    Well-Known Member

    Nov 3, 2012
    Have you checked the original transformer itself - sometimes it shows the polarity.
    If not sure post clear photos.
    What is the Make/Model of the device ?
  7. WBahn


    Mar 31, 2012
    If the original circuit is still intact and functioning at all, just measure the voltage between the center and sleeve and make note of the polarity -- assuming you have a meter. You can determine polarity using an LED and a resistor, too. If it isn't functioning, then look at the polarity of the filter caps and also the rectifier diodes, if you can find either and if you can determine the connections between them and the output jack.

    You might also be able to find out by looking at the documentation or looking at the manufacturer's website.
  8. panic mode

    Senior Member

    Oct 10, 2011
    are you sure it is a DC that device expects?