12 volts CFL polarity

Discussion in 'General Electronics Chat' started by Lightfire, Apr 19, 2011.

Whic is correct/better?

  1. Option 1

    3 vote(s)
    100.0%
  2. Option 2

    0 vote(s)
    0.0%
  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Hello.

    I have two 12 volts CFL rated as 5 watts. I know there is totally no polarity.

    If there is ever is. Please tell it to me. If not, please vote for the best choice...

    Option 1
    [​IMG][​IMG]
    Option 2
    [​IMG][​IMG]
    Please vote...

    Reasons (optional)
     
    Last edited: Apr 19, 2011
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    I looked through 5 manufacturer's websites and none show the polarity for these DC light bulbs. So maybe they are made with a bridge rectifier so polarity doesn't matter?
     
  3. magnet18

    Senior Member

    Dec 22, 2010
    1,232
    124
    Outside is usually neutral I think, but it shouldn't matter either way.
     
  4. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    If the circuit doesn't have a rectifier bridge or an "idiot" diode in series or parallel (to blow the fuse) then its inverter circuit will probably blow up with reversed polarity.
     
  5. magnet18

    Senior Member

    Dec 22, 2010
    1,232
    124
    Did he maybe leave the 0 off the 120?
    making it AC?
    or is it really nonpolar?
    Of course, you could just use an incandecent and save the trouble.
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    12V compact fluorescent light bulbs are used in motor homes.
    They use 10W to 14W of power to make the same amount of light as a 60W incandescent light bulb "heater".
     
  7. magnet18

    Senior Member

    Dec 22, 2010
    1,232
    124
    Weve had this discussion before.
    lets not do it again.
     
  8. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    We need at least ten votes to be satisfied.
     
  9. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The votes are useless because nobody has said they have measured the polarity of one of these light bulbs so they are only guessing.

    I looked in Google (why don't school kids look in Google?) and found some that have polarity protection and others that do not.
     
  10. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    But it doesn't tell where is the negative and positive terminal.
     
  11. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Find one with polarity protection that you can buy.

    Or find one that you can buy and look online at its manufacturer's datasheet.

    The Phocos bulb photo that I posted shows that its end terminal is positive and the screw threads are negative. Maybe all polarity sensitive DC CFL bulbs are wired like that or maybe all polarity sensitive ones are marked with the required polarity.
     
  12. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    The one that I have purchased is the one that have polarity protection. But I asked it because the owner of the hardware told that it's have polarity. but when i check the box, there is no attention for polarity. :) so i test it and all works fine. :)
     
  13. magnet18

    Senior Member

    Dec 22, 2010
    1,232
    124
    I said it earlier, threads are usually neutral or negative.
     
  14. soundman

    New Member

    Dec 27, 2010
    13
    1
    Common lampwire has a slight bump on the neutral side that is wired to the thread of a lamp base and since the lamp in the photo looks like a typical lamp base I'm voting for the center as +.
     
Loading...