Please help identify this part?

Discussion in 'General Electronics Chat' started by phawk, Apr 4, 2013.

  1. phawk

    Thread Starter New Member

    Apr 4, 2013
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    SOT-23 package size 3 pin, can not find any info relating to this item using the code stamped on top?
    Im Assuming its a transistor.

    1st time posting here (anywhere in fact) apologies if i've ballsed it up. :)
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    Could be a mini regulator in the sot package, what its purpose?
     
  3. phawk

    Thread Starter New Member

    Apr 4, 2013
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    The circuit is from a digital photo frame, not sure what the components purpose is. 5v comes from the power jack, through a coil into a capacitor and then 5v is present on both legs of the component (the 2 on the same side) but no power emerging from the other side and no power to rest of board.
    and thanks for the quick response!
     
  4. phawk

    Thread Starter New Member

    Apr 4, 2013
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    i have now found this item is not the problem it is operating as some sort of switch and powers up when holding down the tactile switch.
    my head scratching will continue
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    It's a PFET on the +5v rail to be used as a switch when it's gate is at 0v (as you already found out).

    SMD 3-pin regulators almost always have two caps (on Vin and Vout, caps to GND plane) mounted very close to the regulator (which are not shown here on your photo).
     
  6. phawk

    Thread Starter New Member

    Apr 4, 2013
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    Thanks for the info. There is a cap either side.
     
  7. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    1,305
    Not close enough to the device!

    It's not just the caps, you can see the high current traces are pins 2 & 3, and pin 1 is a very low current control signal. So pin 1 is used to turn it on;

    FET;
    pin1 gate
    pin2 drain
    pin3 source
     
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