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iPad power supply

Discussion in 'Troubleshooting and Repair' started by tedstruk, Jun 29, 2017.

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  1. tedstruk

    tedstruk

    475
    7
    Jan 7, 2012
    I found warts for these, online that deliver 12w for the iPad. I did some math
    where 1 amp is there and 12 watts are there and there is 12 resistance there.
    w / i = v
    v squared / 1 i = r

    144/12=12r
    12w/1i=12e

    is the 12r arbitrary? no I think not! so

    144/12=12w
    (1*1)12=12w
    12x1=12w

    so 1(2)amp,12r,at 12v should charge the iPad,,, someone left the adapter at home...needs to charge from 2% battery,,, Why won't it charge through my Pc's USB port?
     
  2. davenn

    davenn Moderator

    13,765
    1,920
    Sep 5, 2009
    only if there is 12V

    I have no idea what these resistors are that you are referring to ??
     
  3. tedstruk

    tedstruk

    475
    7
    Jan 7, 2012
    no resistors as of yet, I want to slap a cheap one that works togther for emergency use...
    I have no specs so I didn't know where to start, I only have the 12w spec from ebay.
     
  4. tedstruk

    tedstruk

    475
    7
    Jan 7, 2012
    ipad at 2%, The PC usb port did 52% overnight
     
  5. tedstruk

    tedstruk

    475
    7
    Jan 7, 2012
    I learned that the conditions nessesary to charge a battery was .oo2 amps. The ones in my radios are 18.85mah. Thats .002 close .01885 the radios use. But I was listening to some guys at a shop and they were talking watts.
    I thought watts were how much power something was capable of handling. Anyway when I told them what I knew, they said it was all numbers and ignored me.

    This is really the first chance I have had to research the watt thing.

    I think the numbers in the equasion that I am looking for are similar... .002w .002a .002v .002r?
    when all thats right, the battery takes a charge... and it takes quite a while to charge it!
    NOw capacity, thats what watts is all about right? and a fancy LIon battery is designed for fast charge, probably around 4 or 5millis. so I do more math.
     
  6. Bluejets

    Bluejets

    4,492
    957
    Oct 5, 2014
    I think you would need to do some study on the subject as it is clear you have no idea and are jumping to conclusions. ( your own) which are not correct. Plenty of tutorials online.
     
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