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.zukr2cpgo5piw3@desktop-ga2mpl8.lan...   
   > On Thu, 20 Dec 2018 04:22:39 -0000, Clare Snyder    
   > wrote:   
   >   
   >> On Wed, 19 Dec 2018 19:36:51 -0000, "William Gothberg" <"William   
   >> Gothberg"@internet.co.is> wrote:   
   >>   
   >>> On Wed, 19 Dec 2018 17:47:17 -0000, trader_4    
   >>> wrote:   
   >>>   
   >>>> On Wednesday, December 19, 2018 at 11:35:06 AM UTC-5, 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?   
   >>>>   
   >>>> I've never noticed that.  Any films come to mind?   
   >>>   
   >>> A lot of Top Gear programs showing the DRLs of cars fitted with LEDs.   
   >>> With a feature film, they might take the time/trouble/money to do   
   >>> something to stop it.   
   >>>   
   >>>> It seems especially   
   >>>> weird, since cars have a 12V supply with a big battery to smooth   
   >>>> anything out.  I guess the power supply that reduces that to whatever   
   >>>> the LED headlights use though might have a switching power supply these   
   >>>> days too.   
   >>>   
   >>> AFAIK it's deliberate, making the LEDs operate brighter than they are   
   >>> capable of, but only 1/4 of the time.  Our eyes just see the brightest   
   >>> part of the cycle, so we think they're four times brighter than the LED   
   >>> is really capable of, without overheating itself.   
   >>   
   >>  That is PWM Overdrive. Peak junction current is over the nominal   
   >> rating, but the average power consumption is below nominalmaximum   
   >> current - and the peak lumen output is significantly enhanced without   
   >> reducing the junction life appreciably.   
   >>  THIS would definitely cause flicker as there is a "significant" dead   
   >> period between the "strobe flashes"   
      
   > Agreed, although Rod thinks only freaks can see it.   
      
   Its true with car lights.   
      
   > I wonder why none of my houselights use this?   
      
   Hues bulbs do, you can see that by waving something non   
   transparent past a bulb when looking directly at a lighted bulb.   
      
   Your strip house lights have far more leds so don't need to.   
      
   > Do car lights have to make more brightness from a smaller area?   
      
   Corse they do.   
      
   > Or would flickery houselights annoy people more?   
      
   They don't with Hue bulbs.   
      
   > If it's the extra brightness, I don't understand   
      
   As always.   
      
   > because I have a torch with a single LED and parabolic reflector that   
   > gives out 20W equivalent without overdrive.  Simply have three such lamps   
   > with their own little (only 1.5 inches across) reflector next to each   
   > other to make the headlamp.   
      
   Even you should have noticed that car headlights are much brighter.   
      
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