Can I substitute a 12VDC 100mA plug-in-the-wall power supply with a 12VDC 800mA supply?

A 100mA supply I have, which worked fine, is now broken. I also have a 800mA supply. Since they both have12VDC outputs, but the mA outputs are different, can I swap the higher mA for the lower mA and not have a burn-out problem?

9 Answers

  • Anonymous
    1 decade ago
    Best Answer

    All this means is that you will now have eight times the capacity you had before. As long as the waveform is properly rectified and filtered so the voltage output is the same, your load will never "know" the difference.

    Source(s): Electrical Engineer 26 years
  • 1 decade ago

    The power will not be a problem. The only cautions doing this kind of switchover are:

    (1) Make sure that the polarity of the two power supplies are the same. For example, somtimes the outer contact is positive and the inner contact negative, and sometimes it is the other way around.

    (2) Power supplies are not all equal. In the conversion from AC to DC some power supplies produce a clean signal while others produce a voltage that fluctuates up and down. In general, a transformer that is being used for electronics can be used for a different piece of electronics since these tend to produce "clean" signals. Transformers for other stuff like charging your 20 year old electric razor may not be as suitable.

  • "Poor one" sort of has a point, But, since he couldn't be bothered to explain in any detail, suggested ignoring all the other answers, and it seems that he may have given everyone else a thumbs down, I recommend ignoring him on the grounds that he is a <redacted>.

    I believe that the point he was trying to make is that some devices may depend to some extent on the internal resistance of the power supply for proper operation, and a higher current supply will have a lower source impedance. I suspect that is unlikely to be a significant issue, but you should be aware that it is at least a possibility.

    Knowing more details about the power supplies and what is being powered would be helpful..


    "poor one" said: "Also, don't forget that people breaking the code of conduct should be reported."

    Well, I'm not so sure about that, true enough the community guidelines do say "Being mean or obscene" is wrong, but I think "mean" is subjective, and one should use common sense. You insulted 6 people

    "Please ignore all the above, that answer when they don't know."

    but I did not think that was worth reporting. While I do admit it may have been inappropriate. I only insulted one person. (and the word I used wasn't all that bad, in fact, in engineering it is the term for the rate of change of acceleration, though of course I didn't use it in that context.)

  • J C
    Lv 5
    1 decade ago


    The only issue might be making certain that the polarity is correct.

    (Plus +, and Minus -)


    poorone and tinkertailor both have good points about loading the supply.

    An easy fix would be to use a voltmeter to check the unloaded and then the loaded voltages.

    If the unloaded voltage was near 12V. (say no more than 13.5V.) it is probably safe for most devices.

    Testing the voltage with the load hooked up (for a few seconds) is probably safe as well.

    I say "probably" because I cannot and will not be responsible if you damage your device.

    (I am saying this because if the device was a life-support device I would not do this unless it was an emergency!)

    If the loaded voltage was above about 12.5V; I would be careful about using it continuously. (Feel it occasionally to see if it gets hot.)

  • How do you think about the answers? You can sign in to vote the answer.
  • Rose
    Lv 4
    4 years ago

    why? if it really takes the full 10 amps, just go with a straight battery charger and forget about the battery. you might need to install a couple of filter capacitors to clean up the 12v dc a bit more.

  • 1 decade ago

    No problem. The current rating means it is capable of up to delivering 800 mA, doesn't mean it would constantly delivering that current.

  • 1 decade ago

    No, If these are unregulated supplies, you will have too high voltage. Please ignore all the above, that answer when they don't know.

    Edit - Also, don't forget that people breaking the code of conduct should be reported.

  • Anonymous
    1 decade ago

    If your application is not to charge batteries then maybe it is ok.

  • Anonymous
    1 decade ago

    it will work just fine

Still have questions? Get your answers by asking now.