XPost: alt.home.repair, uk.d-i-y   
   From: Gothberg"@internet.co.is   
      
   On Fri, 21 Dec 2018 01:11:53 -0000, Rod Speed  wrote:   
      
   >   
   >   
   > "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.   
   >>>>>>>   
      
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