XPost: alt.home.repair, uk.d-i-y   
   From: Gothberg"@internet.co.is   
      
   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.   
   >>>>   
   >>>> You must know some people with really shitty eyesight.   
   >>>   
   >>> I'm talking about everyone at work. NOT ONE could see that.   
   >>   
   >> What age group were they in?   
   >   
   > All of the, everything from those straight out   
   > of school to those who were about to retire.   
   > And the kids of many of them as well.   
      
   How odd.  I can't believe Aussies have different eyes to Brits.  More sunlight   
   in the room maybe?  Having 90Hz CRTs to avoid flicker was quite common around   
   the world, go google it.   
      
   >>>> I noticed that more people who were younger and/or didn't wear specs   
   >>>> could   
   >>>> see the flicker.   
   >>>   
   >>> Don't buy that either. None of the kids could see it.   
   >>   
      
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