bench power supply unit

Discussion in 'General Electronics Chat' started by Steve Cornwall, Aug 20, 2014.

  1. Steve Cornwall

    Thread Starter New Member

    Aug 20, 2014
    2
    0
    hi,

    I have done some electronics in the past (I used to teach physics) and have built some computer orientated devices.
    so I am not completely ignorance, however my knowledge is more theoretical out of a book rather than practical.
    I now find myself in the position where I can pursue this hobby more vigourously.

    My projects will tend to be computer, robotics oriented although one of the first things I wish to investigate are - Peltier coolers (I want to keep my pasties hot and my beer cool on my mobility scooter).

    the little bit of research I have done so for seems to indicate that these devices will run away if the current is not limited.

    I am therefore looking for an affordable bench powersupply. I need to be able to set the maximum current a device can draw from the power supply.

    I am looking at a Maplin product-
    100W Slim Bench Power Supply



    I would be grateful for comments as to whether this is the way to go for a reasonably priced bench power supply that well do what I need to do.



    Thanks,


    Steve
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    Looks ok to me for a general purpose bench power supply.

    If you are experimenting with simple circuits, both analog and digital, I would also consider have the following on hand:

    1. 9V batteries and battery clips
    2. 1.5V batteries and battery holders (size AA)
    3. 8VDC 500-1000mA wall adapter plus 5VDC regulator
    4. or a fixed 5VDC regulated wall adapter
    5. dual +/- DC supply, (fixed dual 9-15VDC) 200-500mA, again from a wall adapter.

    If you hunt around you can find a plug-in adapter with triple outputs, +5V, +12V, -12V that you can used for prototyping projects.

    Another good idea is to build yourself a breadboard with built-in +5V, +12V, -12V supply.
    While you're at it, make sure you add a +3.3V supply.
     
  3. Steve Cornwall

    Thread Starter New Member

    Aug 20, 2014
    2
    0
    Thanks,Useful Comments.

    Steve
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    Oh, by the way, I usually don't source my components (as above) new from main stream suppliers. I hunt around for discards, recycling, junk, surplus and second hand stores.

    I can pick up a suitable wall-wart for a quid or two.
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,986
    745
    If you just want 3v, 5v, 12v, use an old Atx psu as a bench type, easy to convert
     
  6. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    I think you will be doing a lot of low voltage stuff.

    The Maplin supply does not go down to zero volts, that is a serious shortcoming for a proper bench supply.

    Also remember that at 1v out and 5A you are dissipating nearly 100watts inside the supply. This is partly why these far eastern supplies have a poor reputation/life expectancy.

    You would be far better spending £30 on a reputable make second hand laboratory /bench supply from E_ay.
    These go down to zero and you are likely to pick up a twin plus-zero-minus supply to boot.

    If money is tight you can always use spare cheap multimeters for the metering, better the manufacturer has spent money on power supply than meters.
     
  7. adamclark

    Member

    Oct 4, 2013
    472
    6
    check out Astron PSU's,,, I used them at the shop for years now,, I've got a +/- 0-24vsc adjustable 60a supply that ive used at 3.3v for hours all the way up to 20v for hours at a time.. Very reliable supplies..
     
  8. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    If you are going to go with Maplin, I reckon this PSU is well worth the extra £10..

    http://www.maplin.co.uk/p/80w-switched-mode-dc-multi-voltage-slim-bench-power-supply-n27gg

    Similar specification, but has a quality look and feel to it, and has sense wires to give a much more accurate and better regulated supply at your device. LED readout is easier to read too. Goes down to 0.1V.

    One day you may need dual +/- supply (or two single supplies) though, especially if you want to experiment with op-amps.

    Both Maplin supplies are small, neat and handy for home/hobby use.

    (something tells me that 20V might be not quite enough for robotics - some stepper motors might want 24V or more? - but I could easily be mistaken)

    .... and won't peltier devices want big current? ....again just guessing
     
    Last edited: Aug 20, 2014
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