single-phase input => 10-20V DC output

Discussion in 'General Electronics Chat' started by Kidlike, Oct 11, 2010.

  1. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    Hi all,

    As the title says I am looking for a circuit that implements this.
    From the single-phase (in the house wiring) I want to obtain a 10 or up to 20V DC power supply.

    The power supply module I want is meant for usage inside a wall switch; thus the single-phase input.

    The only thing I have found that could help me do this is a "current transformer" but I don't know how to use it. Also maybe there is a better solution.

    As you already might have figured, space is a concern.. (inside a wall-switch)

    Thanks a lot in advance!
    /*Stef*/

    PS: I am a micro-electronics guy so I wouldn't know about AC and phases stuff.. sry! :/
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    U need a switch mode supply if space is limited but for that we need to know the power rating of the load
     
  3. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    220V @ 50Hz (I think 50Hz.. maybe 60)
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    U are not tht well informed on these kinda things aren't ya.
    I am not talking abt frequency.

    What wud u be using to power up from this supply.
    A bulb or LED strings.
    What is the load requirement.

    A supply is stated for it's power output. Which includes Voltage and Current rating
     
  5. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Yes, you did. I got wrong stuff.
     
    Last edited: Oct 11, 2010
  7. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    oh sry R!f@@ :)

    I need about 500mA max..

    I will have a pic with 16pins and an RF transceiver. Maybe also some IR leds..
    Typically I could limit the use to 200 or 300mA. But to be sure for future usage let's say 500mA.

    Thanks!

    edit: all these components need 5V
     
  8. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Check for 12V to 14V @ 500mA Transformer tht is order with ur mains.

    But with this u need to know the space constraint like u said. Donno if u cud fit a transformer with the electronics tht u need.
    If not possible and u need to go for smaller ones,. then u definitely need a little SMPS.
    They will be smaller, lighter and better but will be expensive and difficult to built than a standard transformer supply
     
  9. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    Maybe I didn't explain it well..

    I can't use anything already built.

    The module will be placed behind the wall-switch.
    So I need to get power from the cables that go to the light.

    Or maybe I didn't understand your answer. lolz
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Yes I know what u want.

    U want a power supply to power ur ckt.
    Question is tht can u fix a transformer tht I suggested, for this u need to get a transformer and check.

    If not then u need a SMPS one. They a much smaller, but keep in mind tht these types some times needs ventilation to avoid failure in prolonged usage

    I suggest u get a transformer and make a bit of more space in the wall
     
  11. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    Can you suggest me how to build the transformer?
    what parts I need?

    I can get more hands-on help if I have the general guideline.

    Thanks for your help again
     
  12. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Sorry ..u cannot build a transformer.

    Any one who asks this does not have any tools for this
     
  13. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    So I have to get a transformer, and then adjust it to get it's power source from the cables ?
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    U do not need to adjust anything. Buy a transformer with 4pc IN4001 diodes and 1 pc 1000uf 25V capacitor.

    Come back here, and I will guide u to make a PSU.

    Check the local store for these items.
    A little note on tx. input is 240VAC. output should be between 12V to 15VAC. Secondary current rating shud be 500mA.
    Also buy two fuses. One 100mA and 500mA. Get the fuse holders too.
     
  15. marshallf3

    Well-Known Member

    Jul 26, 2010
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    The problem here is there are no "mains" voltage across a switch as there's the load connected in series with one of the wires leading to it. When the switch is off there will be voltage across it but that's because you're reading through the load.

    Switches are usually hooked up with the hot supply coming in and the switched voltage going out to the load but there's rarely a neutral wire in the box.

    What is this circuit supposed to do?
     
  16. Kidlike

    Thread Starter New Member

    Oct 11, 2010
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    The circuit is supposed to be able to change the state of the switch, and also transmit (to an other module[/server side]) the current state of the switch.

    I know that it is possible to be done because there is such a module by the X10 protocol (seen at lasers.com). Actually my only problem is the power supply. The RF transceiver has quite the consumption.

    I could place a small circuit between the switches ends in order to achieve a permanent load, but not enough for the lamb to turn on. After all, I need only 10VDC.
     
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