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Thread: Suitable mulitimeters

  1. #21
    fly Guest
    Quote Originally Posted by dennis13030 View Post
    Hi,

    My name is Dennis and I am an electronics engineer. The low cost and high current way to go is this;

    1. Buy a cheap digital multimeter(the max current rating is NOT important). Believe me on this.
    2. Buy a current sensing resistor. See this link. It is a 0.005 Ohm, 7 Watt resistor and it's real cheap($4.16).
    http://www.mouser.com/Search/Product...KYZDPMxg%3d%3d
    3. Put this resistor inline with the +12V against the electrolyzer.
    4. Use the voltmeter to read the voltage across the sense resistor. Whatever value is displayed, multiple it by 200 for the true current value. This calculation is due to the resistor being 0.005 Ohms.

    This gets your cheap DMM an effective maximum current measurement of about 37 Amps.
    Whoa, I was looking for exactly that... Didn't think of that at all although it makes perfect mathematical sense.
    Thanks Dennis, I will definitely try it out... Need to measure current WAY stronger than 10 amps which is the max my amp meter is rated for (although it displays up to 19.9 amps).

    Thanks! should have thought of it, but hey, I'm no electronician, just a hobbist!

  2. #22
    c02cutter Guest
    If you plan on doing any testing at all, and plan on using it in the furture, buy a fluke!

  3. #23
    Join Date
    Jul 2008
    Posts
    1,174

    Question

    Quote Originally Posted by c02cutter View Post
    If you plan on doing any testing at all, and plan on using it in the furture, buy a fluke!

    Not unless you are willing to accept "fluke" readings with a non-Fluke meter.

    BoyntonStu

  4. #24
    AzDad Guest
    Dennis-i have a multimeter does not have a amp reading on it , but it does have a millie amp . How would you convert the reading? Thx Tim

  5. #25
    dennis13030 Guest
    Quote Originally Posted by AzDad View Post
    Dennis-i have a multimeter does not have a amp reading on it , but it does have a millie amp . How would you convert the reading? Thx Tim
    Is it a digital multimeter and will it read voltages in the millivolt range?

  6. #26
    HHO King Guest

    30 Amp Heavy Duty Pulse Width Modulator-PWM with Gauge!

    Quote Originally Posted by Painless View Post
    Whilst visiting Home Depot / Lowes etc for other bits and pieces, I've also been looking around for a multimeter that I can use to reliably monitor the DC current amps etc on my unit, once it is built and in the testing phase, however, the best ones I can find only seem to go to a maximum current of 10 amps DC. I'm hoping to find a multimeter that will measure up to 30 odd amps, but won't break the bank.

    Can any of the electronics guru's recommend a source?
    I would recommend a unit like this. I saw it at Extreme HHO.

    http://www.extremehho.com

  7. #27
    sheriffav8r Guest
    I'm going to get this one for HHO and around the house/car:

    http://www.sears.com/shc/s/p_10153_1...82369&sLevel=0

    Not bad at $60 for 400A AC/DC.... Plus a nice temperature probe, to boot!

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