Y DC jack has 3 lugs?

Discussion in 'General Electronics Chat' started by mxabeles, Apr 27, 2009.

  1. mxabeles

    Thread Starter Active Member

    Apr 25, 2009
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    0
    I want to solder up a DC jack for an adapter but I am confused. The plug from the adapter seems to have two points of connection, positive and ground. Why then does the jack have THREE lugs?
    I have tried researching this thoroughly but with no avail.

    Thanks,
    Max
     
    Last edited: Apr 27, 2009
  2. bertus

    Administrator

    Apr 5, 2008
    15,638
    2,343
    Hello,

    Can you post a picture?
    Is it for input?
    The third lug may be for switching.

    Greetings,
    Bertus
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Some DC jacks have a 3rd connection that can be used to switch between internal battery power and external "wall-wart" power.

    It can also be used to apply a ground to discharge internal filter capacitors rapidly, in case the circuit is logic level and operation at low voltage is not desireable.

    You'll need to use a meter with a plug inserted into the jack to determine which terminals are "live" when connected.
     
  4. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    Also, it could be a stereo jack.

    Ken
     
  5. mxabeles

    Thread Starter Active Member

    Apr 25, 2009
    182
    0
    You'll need to use a meter with a plug inserted into the jack to determine which terminals are "live" when connected.


    "yeah, that is the best solution"
    simple thanks
     
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