DIY Your Own Ammeter

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  • jeremykum
    Senior Member
    • Feb 2012
    • 95
    • Malaysia

    #1

    DIY Your Own Ammeter

    I am not sure if anyone had this posted, but thought it might be useful for people on a budget or those that do not need a Power Supply Bench yet.

    Using a Digital Multimeter, use it as a Ammeter.

    Things you need:

    1. A good universal power adapter (I am using Acbel), which has auto cut when detect shortage. With multiple socket type to fit various laptop models.

    2. A reliable good quality Digital Multimeter (with 10Amp jack). I am using a basic Kyoritsu model about USD40 (equivalent to my currency)

    3. 1 set male/female socket with 3 (2 also is fine) pins.

    4. Soldering material most likely we all have already.

    5. One extra set of multimeter probe, just need the wire as the probe need to be cut off.

    Connections:
    DC Output +ve to DMM (Amp) +ve
    DMM Common (-ve) to DC jack +ve
    DC Output -ve to DC jack -ve

    By reading the ampere drawn when troubleshooting boards, I could roughly guess which part I need to fine tune my checking. The more you use this method, the more you will sharpen your diagnosis. Also you can try to take notes of the boards that work normally how the ampere is drawn.

    Example:
    CQ40 AU-series, boot stuck at 0.9A, usually tells me the IGP is gone.

    Each generations of designs has different values. Picture shown is Asus K43U, fully boot draws only 0.875A (I only attach processor, fan, memory) without LCD screen, as I usually attach display to external monitor. Just the basic items to get the board startup.
    Attached Files
    Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.
  • Kiriakos GR
    Banned
    • May 2012
    • 940
    • Greece

    #2
    Re: DIY Your Own Ammeter

    No one would pay for a professional power supply if the current limiter functionality was not that significantly important.

    Comment

    • SteveNielsen
      Retired Tech
      • Jun 2012
      • 2327
      • USA

      #3
      Re: DIY Your Own Ammeter

      Short protection is current limiting.

      Comment

      • jeremykum
        Senior Member
        • Feb 2012
        • 95
        • Malaysia

        #4
        Re: DIY Your Own Ammeter

        Originally posted by SteveNielsen
        Short protection is current limiting.
        I think what Kiriakos GR means is the ability to supply the required voltage at limited current for testing purpose and not burning up the electronics.

        I do wish soon, I can have a power supply bench in my workshop.
        Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

        Comment

        • SteveNielsen
          Retired Tech
          • Jun 2012
          • 2327
          • USA

          #5
          Re: DIY Your Own Ammeter

          You are correct. My mistake.

          Comment

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