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need help with dc adapter

Discussion in 'General Electronics Discussion' started by hexacode, Aug 14, 2013.

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  1. hexacode

    hexacode

    2
    0
    Aug 14, 2013
    long story short. im at a thrift store and found a router needing 12v dc and 1 amp.
    theres a separate section in store with adapters and i found only 1 12 v dc adapter but its at 200 miliamp. i know for a fact that amp is dictated by the resistor on the circuit, in this case the wifi adapter would be the resistor. so question is will the device, rated at 12 ohms obviously, try to let through 1 amp with the adapter? also, does the 200 miliamp meand just dont go over else it gets fried? or does the adapter have some built in resistor limiting it at 0.2 amps or some other limiting mechanism ?
     
  2. davenn

    davenn Moderator

    13,654
    1,888
    Sep 5, 2009
    hi there
    welcome to the forums :)

    well yes ... the LOAD on a circuit diagram may be shown as a resistor BUT don't be fooled
    you can also have inductive loads and for that matter capacitive loads ... or a mixture of all 3.
    The thing to remember is ... the combination of ALL the components is a device make up the load and unless its something specialised like say an
    antenna. then the load can be generally though of as an overall resistive load

    It will try to draw 1A from the power pack but of course if the pp cannot supply it, then the device wont work properly.
    Yes, a pp rated at 200mA means that is the max load before the pp starts to heat up and yes may cook.
    No, not usually any resistor in there limiting the current.
    The main current limiting comes from the ratings of the transformer in the pp
    Secondary will be a voltage regulator ( if present), will also have a current limiting feature

    cheers
    Dave
     
    Last edited: Aug 14, 2013
  3. hexacode

    hexacode

    2
    0
    Aug 14, 2013
    long story short. im at a thrift store and found a router needing 12v dc and 1 amp.
    theres a separate section in store with adapters and i found only 1 12 v dc adapter but its at 200 miliamp. i know for a fact that amp is dictated by the resistor on the circuit, in this case the wifi adapter would be the resistor. so question is will the device, rated at 12 ohms obviously, try to let through 1 amp with the adapter? also, does the 200 miliamp meand just dont go over else it gets fried? or does the adapter have some built in resistor limiting it at 0.2 amps or some other limiting mechanism ?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,412
    2,780
    Jan 21, 2010
    Just a random thought hexacode, but checking your original thread before asking exactly the same question a second time would seem to be... wise?
     
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