Help with a DC-DC Step Down Regulator Please?

Discussion in 'The Projects Forum' started by laser33904, Feb 23, 2012.

  1. laser33904

    Thread Starter New Member

    Feb 7, 2012
    2
    0
    I purchased a couple of these small:
    DC to DC Buck Converter Step Down Voltage Regulator Module 3-30V to 1.21-18V

    http://www.ebay.com/itm/140691534926?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l264

    And can't seem to set the voltage out. I have 9 VDC going in and no mater which way I turn the "pot", I have 9 VDC coming out. I am going to power a 532 nm laser module with a driver that requires 3 VDC and no more. I've tried a full turn in both directions and can't get it to drop. I know that these pots have "sweet spots" and flat spots sometimes and don't want to break it by going to far.

    What am I doing wrong?

    Thanks for any replies,

    Newb:)
     
  2. #12

    Expert

    Nov 30, 2010
    16,354
    6,852
    That's a multi-turn trimpot. Might have 10 turns or even 20. Probably ratchets at the end. Try it again.
     
  3. radiohead

    Active Member

    May 28, 2009
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    31
  4. laser33904

    Thread Starter New Member

    Feb 7, 2012
    2
    0
    Thanks for the reply.

    I didn't know if this pot would break turning and turning it.


    I'm up in Illinois with my wife helping her mom and dad through some rough medical times and am limited with the amount of stuff I have available to work with. I have a whole bunch of tools back in my garage in Florida. I only have a small amount of hand tools and a butane soldering iron in a bag I keep in my vehicle.

    I'm building my Grandson a 4 motor Spirograph Laser.


    Can I split the 9 VDC coming into my project box from my desktop power supply and run my motors and fan's (which are 9 and 12 VDC) and pick-up my 3 VDC for my laser module from the Buck step down module OK or will that be a problem?

    I want to stay away from batteries.


    Thanks for the help!
     
  5. #12

    Expert

    Nov 30, 2010
    16,354
    6,852
    I have run assembly lines installing that kind of pot. Way less than one in a thousand breaks when adjusted by people with a high school education.

    Can you run more than one load off your power supply? Probably. If it can supply enough current it will work.
     
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