Current sensing

Discussion in 'The Projects Forum' started by t4khan, Mar 6, 2010.

  1. t4khan

    Thread Starter New Member

    Mar 4, 2010
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    0
    Hi,

    I am trying to design a circuit which does power measurments in an 120VAC line at home between the mains and the device in a digital form.

    So far I realize that to measure power, I should use current sensing circuit like INA138 (http://www.ti.com/lit/gpn/ina138) and use its output to an ADC to get an output in a digital format.

    Can the INA138 work with AC circuits in the first place? If not, are there any alternatives?

    What is the best way to design a circuit that can be inserted between the mains and the device connected to the mains to measure the power used by the device in a digital format?

    Please note that I am a 4th year Electrical Engineering student and will understand any complex terminology that you man use :). I welcome all to comment on this =).

    Thanks
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    120VAC will blow the lid right off an INA138. It's designed for low voltage.

    Look at using Hall-effect sensors, or current transformers.
     
  3. t4khan

    Thread Starter New Member

    Mar 4, 2010
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    lol.

    I realized that and that's why I would have used step down VT. It's not a very efficient method but I wanted to actually know if it would work with low AC voltages or not. So it will work with low AC right?

    I found something else that would give me exactly what I wanna do.

    I found ADE7753 (http://www.analog.com/static/imported-files/data_sheets/ADE7753.pdf). This is giving me all the readings that I want but this seems more complicated than just putting pieces together. It requires programming...

    I will look into hall effect and CTs but in the meanwhile, do you think ADE7753 is nice and simple solution or can I do better from this list for single phase metering: http://www.analog.com/en/analog-to-...ent/products/index.html#Single_Phase_Metering
     
  4. t4khan

    Thread Starter New Member

    Mar 4, 2010
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    That is an awesome suggestion as well.

    Thanks for the recommendations :)
     
  5. t4khan

    Thread Starter New Member

    Mar 4, 2010
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    This may sound stupid but I am doing this for the fist time. So I hope someone can answer this for me.

    I am going to buy ADE 7566 (http://www.analog.com/en/analog-to-...rgy-measurement/ade7566/products/product.html). I want to program the chip but the problem is that I don't understand how I will do that.

    I dont think the chip can be used with a breadboard. The pins look like they are for soldering only. I have no idea what I should solder this thing on or through what interface I can access it.

    Can someone guide me?

    Thanks.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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  7. t4khan

    Thread Starter New Member

    Mar 4, 2010
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