XPost: alt.home.repair, uk.d-i-y   
   From: rod.speed.aaa@gmail.com   
      
   "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   news:op.zuce1ymco5piw3@desktop-ga2mpl8.lan...   
   > On Thu, 20 Dec 2018 22:22:41 -0000, Rod Speed    
   > wrote:   
   >   
   >>   
   >>   
   >> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   >> news:op.zucc6l1ao5piw3@desktop-ga2mpl8.lan...   
   >>> On Thu, 20 Dec 2018 21:50:21 -0000, Rod Speed    
   >>> wrote:   
   >>>   
   >>>>   
   >>>>   
   >>>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message   
   >>>> news:op.zucbp2igo5piw3@desktop-ga2mpl8.lan...   
   >>>>> On Thu, 20 Dec 2018 21:04:01 -0000, Rod Speed   
   >>>>>    
   >>>>> wrote:   
   >>>>>   
   >>>>>>   
   >>>>>>   
   >>>>>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in   
   >>>>>> message   
   >>>>>> news:op.zub0oriqo5piw3@desktop-ga2mpl8.lan...   
   >>>>>>> On Thu, 20 Dec 2018 17:13:52 -0000, trader_4    
   >>>>>>> wrote:   
   >>>>>>>   
   >>>>>>>> On Thursday, December 20, 2018 at 12:07:40 PM UTC-5, William   
   >>>>>>>> Gothberg   
   >>>>>>>> wrote:   
   >>>>>>>>> On Thu, 20 Dec 2018 16:25:22 -0000, trader_4   
   >>>>>>>>>    
   >>>>>>>>> wrote:   
   >>>>>>>>>   
   >>>>>>>>> > On Thursday, December 20, 2018 at 7:29:53 AM UTC-5, William   
   >>>>>>>>> > Gothberg   
   >>>>>>>>> > wrote:   
   >>>>>>>>> >> On Thu, 20 Dec 2018 11:57:01 -0000, whisky-dave   
   >>>>>>>>> >>  wrote:   
   >>>>>>>>> >>   
   >>>>>>>>> >> > On Wednesday, 19 December 2018 16:35:05 UTC, William Gothberg   
   >>>>>>>>> >> > wrote:   
   >>>>>>>>> >> >> On Wed, 19 Dec 2018 16:21:41 -0000, Mark Lloyd   
   >>>>>>>>> >> >>    
   >>>>>>>>> >> >> wrote:   
   >>>>>>>>> >> >>   
   >>>>>>>>> >> >> > On 12/19/18 6:01 AM, William Gothberg wrote:   
   >>>>>>>>> >> >> >   
   >>>>>>>>> >> >> > [snip]   
   >>>>>>>>> >> >> >   
   >>>>>>>>> >> >> >> They probably are fairly crude.  I know they flicker, for   
   >>>>>>>>> >> >> >> example if I   
   >>>>>>>>> >> >> >> use my cordless drill, the chuck appears to spin the   
   >>>>>>>>> >> >> >> wrong   
   >>>>>>>>> >> >> >> way   
   >>>>>>>>> >> >> >> under the   
   >>>>>>>>> >> >> >> LED lighting.   
   >>>>>>>>> >> >> > I remember seeing that with a washing machine (under   
   >>>>>>>>> >> >> > fluorescent   
   >>>>>>>>> >> >> > lights). As the tub was slowing down, the row of holes   
   >>>>>>>>> >> >> > around   
   >>>>>>>>> >> >> > the tub   
   >>>>>>>>> >> >> > would appear to reverse direction. Same thing with   
   >>>>>>>>> >> >> > (spoked)   
   >>>>>>>>> >> >> > wagon wheels   
   >>>>>>>>> >> >> > in movies.   
   >>>>>>>>> >> >>   
   >>>>>>>>> >> >> It looks absolutely ridiculous with modern cars with LED   
   >>>>>>>>> >> >> headlights in films.  How hard can it be to put a smoothing   
   >>>>>>>>> >> >> capacitor on the output of the power supply?   
   >>>>>>>>> >> >   
   >>>>>>>>> >> > It's easy but that isn't the point. The most efficient way of   
   >>>>>>>>> >> > driving to make maximium power  into the LED means yuo have   
   >>>>>>>>> >> > to   
   >>>>>>>>> >> > pulse the LED's. Using a capcitor to smooth out the DC is yet   
   >>>>>>>>> >> > another mode of inefficincy as it would get warm due to   
   >>>>>>>>> >> > current   
   >>>>>>>>> >> > flow. Indictors in series might be better but then you run   
   >>>>>>>>> >> > the   
   >>>>>>>>> >> > risk   
   >>>>>>>>> >> > of 'radio' interference.   
   >>>>>>>>> >>   
   >>>>>>>>> >> Being inefficient would presumably make it impossible to get   
   >>>>>>>>> >> enough   
   >>>>>>>>> >> brightness out of LEDs that fit into the lamp holder.  The LEDs   
   >>>>>>>>> >> would   
   >>>>>>>>> >> get too hot trying to give out enough brightness for a car   
   >>>>>>>>> >> headlight.   
   >>>>>>>>> >>   
   >>>>>>>>> >> However cars vary a lot, some are easy to detect flickering,   
   >>>>>>>>> >> some   
   >>>>>>>>> >> difficult, and some impossible (with the naked eye).  Perhaps   
   >>>>>>>>> >> they   
   >>>>>>>>> >> just use a higher frequency?   
   >>>>>>>>> >>   
   >>>>>>>>> >> Taillights are pretty bad on a lot of cars, as they dim the   
   >>>>>>>>> >> brakelights by deliberately flickering them.   
   >>>>>>>>> >   
   >>>>>>>>> > Either you have eyes that are way more sensitive to this or   
   >>>>>>>>> > you're   
   >>>>>>>>> > in   
   >>>>>>>>> > a   
   >>>>>>>>> > country that uses different car lights than here in the USA.   
   >>>>>>>>> > There   
   >>>>>>>>> > are a lot of cars with LED lighting, headlights and rear lights,   
   >>>>>>>>> > and   
   >>>>>>>>> > I've never noticed this flickering, nor have I ever heard it   
   >>>>>>>>> > mentioned   
   >>>>>>>>> > before this thread.  I haven't noticed flickering from any LED   
   >>>>>>>>> > lights   
   >>>>>>>>> > I've used either.   
   >>>>>>>>>   
   >>>>>>>>> I can see flicker on a 60Hz CRT monitor, but not on a 90Hz one, so   
   >>>>>>>>> that'll give you an idea on how good my eyes are.   
   >>>>>>>>>   
   >>>>>>>>> Can you see flicker on tailliights if you scan your eyes across   
   >>>>>>>>> the   
   >>>>>>>>> scene?   
   >>>>>>>>   
   >>>>>>>> Like I said, I haven't noticed it in the driving I've done.  Nor   
   >>>>>>>> have   
   >>>>>>>> I   
   >>>>>>>> heard anyone else mention it.  Next time I come across a car that   
   >>>>>>>> has   
   >>>>>>>> LEDs I'll look more closely and see if I can see anything.  If just   
   >>>>>>>> scanning reveals it, you;d think a lot of people would be noticing   
   >>>>>>>> it.   
   >>>>>>>> Scanning is a part of driving.   
   >>>>>>>   
   >>>>>>> I'd estimate about 1 in 5 people can see it,   
   >>>>>>   
   >>>>>> Its nothing like that high and we know that because nothing   
   >>>>>> like that many saw any flickering with fluorescent lights.   
   >>>>>   
   >>>>> Er.... most people I know can see fluorescent flicker.  It doesn't   
   >>>>> annoy   
   >>>>> most of them, but they can detect it.   
   >>>>   
   >>>> Don't believe it. I did have someone at work who could   
   >>>> see it and was asking about how to get it fixed but no   
   >>>> one else could see what she was talking about.   
   >>>   
   >>> About 20 years ago I worked where everyone had a cheap 14" CRT monitor   
   >>> running at 60Hz.  They really bugged me with the flicker.  When I asked   
   >>> everyone about them, 80% couldn't see it, 10% said they were as annoyed   
   >>> as   
   >>> me, and 10% only saw it if they looked for it.  For the 10% and the 10%,   
   >>> I   
   >>> bought some nice 90Hz Iiyama Vision Master Pro CRT monitors.  They   
   >>> absolutely loved them.  The other 80% couldn't see what the fuss was   
   >>> about, and most of them had specs or were older.   
   >>>   
   >>>>> One in five people I know could see 60Hz monitor flickering.   
   >>>>   
   >>>> Don't believe that either and I never had anyone complaining about it.   
   >>>>   
   >>>>> And about the same can see car lights flickering.   
   >>>>   
   >>>> Don't believe that either and clearly the designers can't.   
   >>>   
   >>> A quick google search shows many many people don't like car flicker.   
   >>> Millions of results.   
   >>>   
   >>>>>>> similar to how many can see flicker on a 60Hz CRT computer monitor.   
   >>>>>>   
   >>>>>> Nothing even remotely like 1 in 5 can see that.   
   >>>>>   
      
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