XPost: alt.home.repair, uk.d-i-y   
   From: Gothberg"@internet.co.is   
      
   On Sat, 22 Dec 2018 02:53:46 -0000, Rod Speed  wrote:   
      
   >   
   >   
   > "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   > news:op.zueh0jeqo5piw3@desktop-ga2mpl8.lan...   
   >> On Fri, 21 Dec 2018 23:09:51 -0000, Rod Speed    
   >> wrote:   
   >>   
   >>>   
   >>>   
   >>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   >>> news:op.zud6g7a4o5piw3@desktop-ga2mpl8.lan...   
   >>>> On Thu, 20 Dec 2018 18:55:13 -0000, Rod Speed    
   >>>> wrote:   
   >>>>   
   >>>>>   
   >>>>>   
   >>>>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   >>>>> news:op.zubminnfo5piw3@desktop-ga2mpl8.lan...   
   >>>>>> On Thu, 20 Dec 2018 08:19:58 -0000, gregz  wrote:   
   >>>>>>   
   >>>>>>> Clare Snyder  wrote:   
   >>>>>>>> On Wed, 19 Dec 2018 19:34:57 -0000, "William Gothberg" <"William   
   >>>>>>>> Gothberg"@internet.co.is> wrote:   
   >>>>>>>>   
   >>>>>>>>> On Wed, 19 Dec 2018 18:03:19 -0000, Clark W. Griswold   
   >>>>>>>>>  wrote:   
   >>>>>>>>>   
   >>>>>>>>>> On 12/19/2018 11:36 AM, William Gothberg wrote:   
   >>>>>>>>>>> On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd    
   >>>>>>>>>>> wrote:   
   >>>>>>>>>>>   
   >>>>>>>>>>>> On 12/19/18 5:23 AM, William Gothberg wrote:   
   >>>>>>>>>>>>> Do switch mode power supplies flicker in time with mains?   
   >>>>>>>>>>>>> Specifically   
   >>>>>>>>>>>>> LED power supplies in commercially available domestic lamps. By   
   >>>>>>>>>>>>> in   
   >>>>>>>>>>>>> time, I don't mean at the same 50/60Hz, but anchored to it.   
   >>>>>>>>>>>>> I.e.   
   >>>>>>>>>>>>> if   
   >>>>>>>>>>>>> you   
   >>>>>>>>>>>>> have several such lamps each with their own built in supply,   
   >>>>>>>>>>>>> will   
   >>>>>>>>>>>>> they   
   >>>>>>>>>>>>> all flicker in time, using the mains frequency to keep them in   
   >>>>>>>>>>>>> time, or   
   >>>>>>>>>>>>> will they be random, making the room overall not flicker due to   
   >>>>>>>>>>>>> them all   
   >>>>>>>>>>>>> being random?  And is there any way I can test this?  I tried   
   >>>>>>>>>>>>> taking   
   >>>>>>>>>>>>> photos of them, but my camera only goes as fast as 1/2000th of   
   >>>>>>>>>>>>> a   
   >>>>>>>>>>>>> second,   
   >>>>>>>>>>>>> which shows all the lights at the same brightness each time, I   
   >>>>>>>>>>>>> suspect   
   >>>>>>>>>>>>> the flicker is above 2000Hz.   
   >>>>>>>>>>>>   
   >>>>>>>>>>>> I once had an audio amplifier with a solar cell rather than a   
   >>>>>>>>>>>> microphone   
   >>>>>>>>>>>> for the input transducer. This made it possible to listen to   
   >>>>>>>>>>>> light.   
   >>>>>>>>>>>> The   
   >>>>>>>>>>>> sun is steady, incandescent lights (AC powered) hum.   
   >>>>>>>>>>>>   
   >>>>>>>>>>>> That was 40 years ago. Maybe something like that would work   
   >>>>>>>>>>>> today.   
   >>>>>>>>>>>   
   >>>>>>>>>>> The trouble is I want to compare 2kHz+ from one light with 2kHz+   
   >>>>>>>>>>> from   
   >>>>>>>>>>> a neighbouring light and see if they're in sync.   
   >>>>>>>>>>   
   >>>>>>>>>> Maybe use a dual trace oscilloscope?   
   >>>>>>>>>   
   >>>>>>>>> Haven't got one unfortunately.   
   >>>>>>>>>   
   >>>>>>>>>> Since this landed in alt.home.repair, I gotta ask.  Do you have   
   >>>>>>>>>> single-phase or two-phase?   
   >>>>>>>>>   
   >>>>>>>>> Single.  I'm in the UK.   
   >>>>>>>>  so 50 Htz - you can almost see an incandescent flicker at that   
   >>>>>>>> frequency (at 25 you could)   
   >>>>>>>>   
   >>>>>>>>  (also rules out the previously mentioned "engineer friend")   
   >>>>>>>   
   >>>>>>> Lights flicker at twice the frequency, once for positive cycle, and   
   >>>>>>> once   
   >>>>>>> for negative cycle. LEDs only once unles using a bridge rectifier, or   
   >>>>>>> steady on using DC. Even though blinking they look normal straight   
   >>>>>>> on,   
   >>>>>>> my   
   >>>>>>> brain says something is wrong   
   >>>>>>   
   >>>>>> Some brains (or eyes) seem to be faster than others.  I can easily   
   >>>>>> (and   
   >>>>>> annoyingly) see flicker on CRT monitors below 90Hz, others don't even   
   >>>>>> see   
   >>>>>> the 50 or 60Hz ones.  I can see flicker on 80% of car LED lights,   
   >>>>>> others   
   >>>>>> don't see any.  Designers really ought to account for those of us with   
   >>>>>> better eyesight.   
   >>>>>   
   >>>>> No point in doing that.   
   >>>>   
   >>>> There is when half the population is capable of seeing it.   
   >>>   
   >>> Half the population isnt.   
   >>   
   >> Then you must know a lot of people with fucked eyesight.   
   >   
   > Nothing fucked about not seeing flicker on car lights.   
      
   Your eyes are clearly operating more slowly, at a lower frame rate.   
      
   >>>> Why only sell things suitable for those with shitty eyesight?   
   >>>   
   >>> They are actually designed to work fine for all but freaks.   
   >>   
   >> Why would you call someone with better eyes a freak?   
   >   
   > Worse eyes when you see flicker with car lights.   
      
   No, I see what's really there.   
      
   >>>> If you can't see the flicker that I can, then your eyes aren't as good   
   >>>> as   
   >>>> mine.   
   >>>   
   >>> Nothing good about eyes that see flicker everywhere.   
   >>   
   >> We see what is really there, you don't.   
   >   
   > Still fucked to have all car lights flicker. You're a freak.   
      
   But they are flickering.  Go film one with a video camera, or just look up a   
   video of one.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)