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DC adapter in place of AC?

Discussion in 'General Electronics Discussion' started by BrianL, Sep 29, 2017.

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  1. BrianL

    BrianL

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    Dec 9, 2011
    I have a NiCd powered Black and Decker drill. The original wall wart charger was 9V AC, but was lost. I have a 9V DC adapter, otherwise equal specs. Will that work without issue. I tried it for a couple seconds and it does power it, but I'm concerned that maybe the original 9V AC ends up much less than 9V after conversion to DC.
     
  2. Bluejets

    Bluejets

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    Oct 5, 2014
    Nope....other way.... 9vac approx 12.6vdc
     
  3. BrianL

    BrianL

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    Dec 9, 2011
    in that case, a 9V DC charger won't damage anything then, correct? Other than maybe not giving a full charge. But it's only a 7.2V drill anyway. Why would it have a 9V AC charger?
     
  4. Bluejets

    Bluejets

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    Oct 5, 2014
    Because one bucket of water has to be higher than the other for current to flow plus somewhere in the circuit will be a regulator where a voltage drop occurs.
     
  5. BrianL

    BrianL

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    Dec 9, 2011
    Sorry, what I meant was why they didn't use a DC charger.
     
  6. BobK

    BobK

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    Jan 5, 2010
    Just because there is no electronics in the wall wart if it puts out AC. All the electronics can be inside the drill.

    Bob
     
  7. BrianL

    BrianL

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    Dec 9, 2011
    That makes sense. Though it seems they're rather not have them in the drill.

    Just confirming, I guess people are scared to say yes, but on paper, the 9V DC charger *should* be OK then, correct?
     
  8. Cannonball

    Cannonball

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    May 6, 2017
    Yes
     
    BrianL likes this.
  9. Audioguru

    Audioguru

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    Sep 24, 2016
    If the "7.2V" battery is Ni-Cad or Ni-MH then all 6 cells are fully charged to 1.5V which is a total of 9.0V.
    The charging circuit might need an additional 1.7V for a total voltage needed of 10.7V.
    The original 9VAC charger produced a peak of 9V x 1.414= 12.7V and the fullwave rectifier dropped the output to 10.7V so a 9VDC charger will never fully charge the battery.
     
  10. BrianL

    BrianL

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    Dec 9, 2011
    Thanks a lot, Audioguru. That's what I was thinking.
     
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