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What kind of device I'm looking for?

  1. Jul 24, 2013 #1
    I've several power adapters of cellphones/routers/modems etc lying around at home. I want to find out if they're any good, however I don't have the right devices (cellphones/modem/router) to check them with.

    I only have a voltage tester: http://www.royalmaster.com.co/wordpress/wp-content/uploads/2012/06/fer6-1024x768.jpg

    I know this voltage tester can't determine what I want to accomplish, but just for fun I put it on the tip of my Nokia cellphone's working power adapter (connected to a power source) and as expected it didn't do anything. I'm looking for something economical to show me volts/amps etc. when I put it on the tip of these adapters.

    Thanks in advance!
  2. jcsd
  3. Jul 24, 2013 #2
    you should better use the digital voltmeter which uses magnetic field to determine the voltage. they are useful for a single wire.
  4. Jul 24, 2013 #3
  5. Jul 24, 2013 #4


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    Science Advisor
    Gold Member

    Ummmmm, no.
  6. Jul 24, 2013 #5
    What do you suggest I should use, Averagesupernova?

  7. Jul 24, 2013 #6


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    Science Advisor
    Gold Member

    What I mean by that is voltage is not measured by sensing a magnetic field. Before you do this you should understand the difference between volts, amps, watts, etc. Understand ohms law and how to apply it.
  8. Jul 25, 2013 #7


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    Staff: Mentor

    That voltage tester is only good for high voltages, say 80V and above, owing to the principle on which it works.

    The only 100% reliable way to determine whether an AC adapter is suitable for its intended purpose is to test it with the device it was designed for. But as you say, you don't have those devices at hand. In this case, you can test the output with a voltmeter (set it to AC or DC as appropriate), but this is only a rough indication and tells you nothing about the adapter under load. Some perfectly functioning adapters (ones having more than two output wires) may deliver no or low volts unless connected to the proper device, so don't bin any valuable adapter based on one simple voltmeter reading. :smile:

    If you maintain a collection of surplus AC adapters, you'll be surprised how often something there saves the day. :wink:
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