XPost: alt.home.repair, uk.d-i-y
From: Gothberg"@internet.co.is
On Tue, 25 Dec 2018 17:33:52 -0000, Rod Speed wrote:
>
>
> "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.
You're obviously wrong, just by the number of articles on the internet about
it.
>> 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.
They don't annoy YOU. They probably annoy others.
>> 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.
A car headlight SHOULD be 60W equivalent. So 6W of LEDs, or a few of my
torches per lamp. Quite possible to just have three reflectors just like my
torch, mounted together.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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