power supply current measurement

Discussion in 'The Projects Forum' started by senthil kumar R, Jul 16, 2007.

  1. senthil kumar R

    Thread Starter New Member

    Jul 16, 2007
    1
    0
    I have 28V power supply with max current 3.5A.I want load the power supply from 0A to 3.5A through rheostat and current consumtion and voltage should be displayed. one idea is to rheostat but it will consume more power and size.
    so help me how to implement this in more smart way.
     
  2. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
  3. John Luciani

    Active Member

    Apr 3, 2007
    477
    0
    What you are looking for is called an electronic load (or current sink). An electronic
    load uses a MOSFET and heatsink to dissipate the power. I have an example schematic
    and PCB layout at http://www.luciani.org/geda/util/matrix.pdf

    (* jcl *)
     
  4. techroomt

    Senior Member

    May 19, 2004
    198
    1
    nice schematic john. dynaload used to make a variable load test equipment device which was used to make the testing and adjustment of power supplies easy. however when a quick test was needed, we would use a piece of metal banding strap (1" wide x 75' long), the stuff they use to tie down pallets. i imagine you could use a smaller size. we ran 2 beefy wires to it with stak-ons and bolts to cleaned surfaces. i can't remember the resistance, but was easy to calculate everything from there for a quick test. not pretty but worked.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    'pretty' is highly overrated ;)
     
  6. John Luciani

    Active Member

    Apr 3, 2007
    477
    0
    Thanks.

    For low voltage (<100V) loads I like the Kikusui and the HP (now Agilent) loads.

    (* jcl *)
     
Loading...