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Power supply from a 220v line — Parallax Forums

Power supply from a 220v line

ManuelManuel Posts: 105
edited 2006-06-20 06:35 in General Discussion
Hey
I want to make a power supply for mys basic stamp, but as the electrical line im gonna have is 220v·and·I·dont know what to do to have a safe power supply for my basic stamp.

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Best Regards

Manuel C. Reinhard

Comments

  • GadgetmanGadgetman Posts: 2,436
    edited 2006-06-07 14:39
    If you don't know how to work with 220V AC, I suggest you instead invest in a ready-made PSU.
    A good one(stabilized/regulated, delivering 500mA or more) shouldn't cost too much, and certainly won't burn down the house.

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    Don't visit my new website...
  • ManuelManuel Posts: 105
    edited 2006-06-07 14:58
    yea, i think thats the best. thx

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    Best Regards

    Manuel C. Reinhard
  • aalegadoaalegado Posts: 66
    edited 2006-06-11 18:25
    An ATX PSU for a PC is a great and low-cost alternative to a bench power supply and they typically have dual-voltage (115/220VAC) capability. You can get a decent capacity (say, 300W) PSU in the neighborhood of $30 to $40 and they offer ridiculous current capacities at the voltages you'd commonly need for most electronics projects (20A or more at +5V and 15A or more at 12V...certainly enough current at either voltage to toast the clip contacts in a breadboard not that I've tried [noparse][[/noparse]grin]) and the power is clean and well-regulated.

    The only trick to using an ATX power supply is that you have to short pin 14 on the ATX board connector to ground in order to "soft" turn-on the power-supply on. This is easily accomplished with a, wait for it, paper-clip because pin 14 is adjacent to a ground wire and a paper-clip or suitable _insulated_ jumper wire can be inserted into the connector housing which holds it snug against the pins. Once you have this short in place, the power-switch on the power-supply itself can be used to turn-on/off the PSU.

    The best thing about about using this style of PSU is that the power leads are relatively long, easily extended, and easily connected to a breadboard using a pin-header and the floppy power connector (see photos).

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    I wouldn't connect that if I were you...

    Post Edited (aalegado) : 6/11/2006 6:33:27 PM GMT
    ATX+Floppy Connector Detail.jpg
    1425 x 1900 - 607K
    Breadboard Detail.jpg
    1920 x 1440 - 627K
  • Craig NCraig N Posts: 17
    edited 2006-06-18 23:06
    From a 70s electronics hobbyist reliving his youth [noparse];)[/noparse] You and the ground you walk on are to be worshipped for your paperclip and pictures! jumpin.gif
  • Tricky NekroTricky Nekro Posts: 218
    edited 2006-06-19 17:18
    In everyelectronic compoments shop should be coils for transforming 220V to 12V or 9V... Then you need a diode bridge some caps and a LM2940 or 7805.... the last one your joice...but I recomment 7805!!!cool.gif

    I'll post the schematics by the night!!!

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  • RDL2004RDL2004 Posts: 2,554
    edited 2006-06-19 17:21
    Do they not have AC adapters (wall warts) where you are? That's all you need really. If all you can find is AC to Ac, then you will still need to convert to DC, but at least the voltage is lower and you are isolated from the mains.

    - Rick
  • Tricky NekroTricky Nekro Posts: 218
    edited 2006-06-19 17:27
    Well, a project is a project... It's nice to roll with your own compoments...
    Ecxept from that it's fairly cheaper to make your own wall pack than buy it.... (a 1.5VA is just very fine to me at 12AC (you have to make it DC although...))cool.gif

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    -Rule your Destiny-
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  • aalegadoaalegado Posts: 66
    edited 2006-06-20 06:35
    Jameco carries a line of unregulated DC wall warts...their 12V@500mA unit (#102277CK) sells for under $6. This plus a capacitor (100uF or larger) gives you a decent Vin for a Stamp-based device. It's particularly well-suited for a BS2 OEM board. No Stamp board based regulator? Add a 7805 or LM2940-5 and you've got your 5V regulated power supply for less than $7. If you take this overseas all you need is a 220V-to-110V step-down transformer (#99477PS, $9) and you've got a decent power-supply complete with mains isolation. We're up to $16.

    Need more current? Buy the 12V@1A unit (#105478 and about $9 changing the total to $19).

    I think an ATX PSU is still a bargain compared to this because you get the 110/220 capability built-in plus the current capacity to toast 10W resistors to your heart's content and still power your 5V circuits with nary a hiccup. devil.gif

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    I wouldn't connect that if I were you...
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