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USB voltage / Amp tester not working on Hand Generator?

Discussion in 'General Electronics Discussion' started by tomadom, Jan 13, 2019.

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  1. tomadom

    tomadom

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    Jan 18, 2013
    I have a few of those USB voltage / Amp testers used to test output power of various usb devices.
    They all work fine but I'm having an issue with my hand cranked generator. Originally they all worked on this device, but recently none of them work at all. They don't even light up.

    The USB testers work on everything else, but on the hand cranked generator the display on these devices doesn't show any output at all (when they did before). As mentioned, the screens on these testers don't light up now.

    So I'm assuming something has gone wrong inside the hand generator to stop this from happening. If I connect the hand cranked generator up to my phone and use a Amp Meter app, I can see the output from the generator there, but not on the USB testers.

    Any clues as to why this is? All the testers I have are rated up to 28 volts and I'm only testing a maximum of 6 volts.

    Thanks
     
  2. Bluejets

    Bluejets

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    Oct 5, 2014
    Crank harder...???
     
  3. tomadom

    tomadom

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    Jan 18, 2013
    Haha! Well, that's always a possibility, but what I'm saying is this worked before but I can't get any output for the USB tester to work now. I thought I may have burned something out in the generator.
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    Then how come this works?
    One possibility I can think of is that the output of the generator is not smooth enough to power the USB tester (the tester may be sensible to ripple). Try an additional smoothing capacitor (e.g. 1000µF) across the USB '+' and '-' connection (power, not data!).

    Your generator may have such a capcitor inside which may have broken lose or may have lost capacity due to ageing.
     
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  5. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Can you disassemble for inspection and confirm exactly what is being inside.
    Like Sir Harald . . . . I HIGHLY suspicion there to be a rechargeable battery or a SUPER capacitor inside
    for creating a more uniform power output. The battery family could have deteriorated due to atrophy, while
    a SUPER E cap is VERY less likely.
     
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  6. tomadom

    tomadom

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    Jan 18, 2013
    I think you both make a good point and I believe that is where this is heading. I will try to open this up as I truly believe an internal capacitor could have something to do with this.
    Thanks for the feedback on this, It's been very helpful!
     
  7. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    You could try an added external capacitor first, before opening the charger.
     
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