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.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.   
      
   > similar to how many can see flicker on a 60Hz CRT computer monitor.   
      
   Nothing even remotely like 1 in 5 can see that.   
      
   > Don't most cars have LEDs now?  Or does your area have a lot of older   
   > cars?  People (stupidly) around here seem to like cars that are no more   
   > than 10 years old.  I don't think many cars after 2008 had bulbs.   
      
   > Searching for "LED tail light flicker" without the quotes in google   
   > produces 4.5 million results!   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)