18v transformless supply

Discussion in 'General Electronics Chat' started by guruji, Sep 19, 2008.

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  1. guruji

    Thread Starter Member

    Nov 11, 2005
    29
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    Hi guys first of all sorry for the poor image cause I don't have an editor.
    How can I modify this circuit from 240v supply to 12v led bulb not 18v?
    Thanks
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    That is a very dangerous design. There is no isolation from the mains.

    A transformer will be somewhat more expensive and bulky, but it won't kill you like the circuit you posted very likely will.
     
  3. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    Indeed. The phase will surely be present at the output on both terminals. So even if the voltage between them is just 18V, you will get a shock when touching one, if you don't get killed in the meantime.

    Sorry if I'm not optimistic, but the danger is very real. My advice is not to.
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Use a 12V transformer. They are several orders of magnitude less expensive than funerals or hospital visits.
     
  5. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    yeah, totally uncool and unsafe 'design'.. maybe natural selection's final frontier?
     
  6. guruji

    Thread Starter Member

    Nov 11, 2005
    29
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    Hi guys thanks for the warnings yes it is dangerous but this is for a led bulb which is going to be sigiled in a holder.It is not going to be used like other transformers.
    Any help please?
    Thanks.
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Sorry, it's just too lethal. Buy a wall wart. Do not fool around with any transformerless power supply.
     
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