XPost: sci.electronics.basics, sci.electronics.design, sci.electronics.misc   
   From: pcdhSpamMeSenseless@electrooptical.net   
      
   On 9/6/2014 2:43 AM, piglet wrote:   
   > On 06/09/2014 05:51, Fester Bestertester wrote:   
   >> AC voltage ballasts are superior to DC ballast.   
   >   
   > I would think the ebay sellers desciption is roughly   
   > right. In a DC arc the electrode material will "burn   
   > off" and migrate only in one direction. In AC arc the   
   > wear reverses each cycle and cancels out. This was   
   > known from carbon arc lights back 150years ago.   
   >   
   > I am surprised that any headlamp Xenon arcs are DC   
   > and if they were DC arc then lifetimes would be   
   > very short.   
   >   
   > piglet   
   >   
      
   Normal arc lamps are asymmetrical--they run from DC, and fail quickly if   
   you put them in backwards. Dunno about HIDs.   
      
   Cheers   
      
   Phil Hobbs   
      
   --   
   Dr Philip C D Hobbs   
   Principal Consultant   
   ElectroOptical Innovations LLC   
   Optics, Electro-optics, Photonics, Analog Electronics   
      
   160 North State Road #203   
   Briarcliff Manor NY 10510   
      
   hobbs at electrooptical dot net   
   http://electrooptical.net   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)