Ac adapter question

Discussion in 'General Electronics Chat' started by Blackmagic, Jan 9, 2013.

  1. Blackmagic

    Thread Starter New Member

    Jan 9, 2013
    New guy here so forgive my lack of knowledge.....

    I have a converter unit that runs on either AC
    (or a 9V battery inside).
    I've lost the AC converter for it years ago
    and want to buy a replacment one.
    All I have to go buy is a picture I took of the back of the unit.
    It says "DC-9V".
    Does that mean that any adapter (as long as it has the correct "end" will work?
    I don't see anything about Millamps (or whatever it is called).
    I just dont want to get the wrong adapter and screw it up.
    SAny help would be appreciated.
    I also took a picture of the back of the unit, if that would help you?
  2. bountyhunter

    Well-Known Member

    Sep 7, 2009
  3. tracecom

    AAC Fanatic!

    Apr 16, 2010
    The unit is somewhat unusual in that the positive voltage must be on the outer conductor and the negative is on the inner pin. Most adapters are the other way around, so be careful. Unless there is some protection built in the device, connecting the power with reversed polarity could make smoke.

    What is the make and model of the unit? Have you Googled to see if you can its power requirements on the web?

    Considering that it uses a 9 volt battery, it probably doesn't require much power; I would guess 100mA or less.
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    That picture tells the whole story. A 9V adapter will work fine providing the center is the negative and the outer end the positive. That's what that symbol between DC and (V means. When you pick one make sure the symbol on that one looks the same.

    It doesn't tell us about milliamps so it's a "go fish" situation: buy one, try it, and if it works great, if not, return and buy a bigger one.

    Too little current should not break anything (though it might work weird depending on what it is). Too much current is not an issue: the box only takes what it needs.