XPost: alt.home.repair, uk.d-i-y   
   From: snick@invalid.invalid   
      
   In article , "William   
   Gothberg"@internet.co.is says...   
   >   
   >On Wed, 19 Dec 2018 12:51:53 -0000, Art Todesco  wrote:   
   >   
   >> On 12/19/2018 7:35 AM, William Gothberg wrote:   
   >>> On Wed, 19 Dec 2018 12:18:54 -0000, Rod Speed    
   >>> wrote:   
   >>>   
   >>>> William Gothberg <"William Gothberg"@internet.co.is> wrote   
   >>>>   
   >>>>> Those fake starters people put into fluorescent fittings when they   
   >>>>> put in   
   >>>>> an LED tube.... what's inside?   
   >>>>   
   >>>> A bit of wire between the pins.   
   >>>>   
   >>>>> An LED tube draws power from the two ends, I looked inside one of my   
   >>>>> tubes   
   >>>>> and the two pins at each end are shorted together.   
   >>>>   
   >>>> They don't all do it the same way.   
   >>>>   
   >>>>> The LED PSU takes power from both ends if you see what I mean, it   
   >>>>> expects   
   >>>>> live at one end and neutral at the other.  So why on earth would you   
   >>>>> need   
   >>>>> anything in the starter, even if you left the ballast in?   
   >>>>   
   >>>> Because the simple bimetallic strip starters have the pins   
   >>>> on the starter connected initially and not connected   
   >>>> when it warms up due to the current between the pins.   
   >>>>   
   >>>>> Surely it's best to have the starter open circuit, i.e. just remove it.   
   >>>>   
   >>>> Some do work like that.   
   >>>>   
   >>>>> Does it perhaps in some way negate the inductive nature of the   
   >>>>> ballast to   
   >>>>> be nicer to the LED PSU?   
   >>>>   
   >>>> No it does not. So its better, but not as easy, to disconnect the   
   >>>> ballast as   
   >>>> well.   
   >>>   
   >>> The properly made LED tubes are connected live at one end and neutral at   
   >>> the other.  You just remove the starter, and the LEDs operate in series   
   >>> with the ballast (or directly to the mains if you can be bothered   
   >>> opening the casing and shorting/removing the ballast).   
   >>>   
   >>> So the tubes where they have live and neutral on the same end, require   
   >>> supplying a fake starter instead of just removing it, surely an   
   >>> unnecessary extra expense.  The only reason I can find for making them   
   >>> like this is some daft safety regulation about having live and neutral   
   >>> at opposite ends.  Better insulation required to meet safety standards   
   >>> incase you grab live and neutral with your two hands?  Surely either the   
   >>> casing of the LED tube is metal, which means you can't get a different   
   >>> voltage on each hand, or plastic, which means it won't conduct power to   
   >>> you.   
   >> I just bought some LED 4' tubes that can be wired any way you want.  I   
   >> don't know the internal circuitry, but I do plan to dissect one to find   
   >> out.  These can be powered from one end (either one), both ends and,   
   >> when powering from both ends, the pins can be shunted or not.  There   
   >> seems to be no combination that doesn't work!   
   >   
   >I can think of a way it might be connected, but please look inside to satisfy   
   our curiosity!   
   >   
   >Kinda like a bridge rectifier but with 4 inputs instead of 2 - any pin of the   
   tube being positive goes through a positive diode, any pin being negative goes   
   through a negative diode (as in connected backwards).   
   >   
   >You know, a diagram would be easier: https://www.dropbox.com/s/   
   lfblkmb6pyqyl8/tube.jpg?dl=0   
      
   PLease don't respond if you don't know what you're talking about.   
      
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