XPost: alt.home.repair, uk.d-i-y
From: Gothberg"@internet.co.is
On Fri, 21 Dec 2018 23:09:51 -0000, Rod Speed wrote:
>
>
> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
> news:op.zud6g7a4o5piw3@desktop-ga2mpl8.lan...
>> On Thu, 20 Dec 2018 18:55:13 -0000, Rod Speed
>> wrote:
>>
>>>
>>>
>>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
>>> news:op.zubminnfo5piw3@desktop-ga2mpl8.lan...
>>>> On Thu, 20 Dec 2018 08:19:58 -0000, gregz wrote:
>>>>
>>>>> Clare Snyder wrote:
>>>>>> On Wed, 19 Dec 2018 19:34:57 -0000, "William Gothberg" <"William
>>>>>> Gothberg"@internet.co.is> wrote:
>>>>>>
>>>>>>> On Wed, 19 Dec 2018 18:03:19 -0000, Clark W. Griswold
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On 12/19/2018 11:36 AM, William Gothberg wrote:
>>>>>>>>> On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> On 12/19/18 5:23 AM, William Gothberg wrote:
>>>>>>>>>>> Do switch mode power supplies flicker in time with mains?
>>>>>>>>>>> Specifically
>>>>>>>>>>> LED power supplies in commercially available domestic lamps. By
>>>>>>>>>>> in
>>>>>>>>>>> time, I don't mean at the same 50/60Hz, but anchored to it. I.e.
>>>>>>>>>>> if
>>>>>>>>>>> you
>>>>>>>>>>> have several such lamps each with their own built in supply, will
>>>>>>>>>>> they
>>>>>>>>>>> all flicker in time, using the mains frequency to keep them in
>>>>>>>>>>> time, or
>>>>>>>>>>> will they be random, making the room overall not flicker due to
>>>>>>>>>>> them all
>>>>>>>>>>> being random? And is there any way I can test this? I tried
>>>>>>>>>>> taking
>>>>>>>>>>> photos of them, but my camera only goes as fast as 1/2000th of a
>>>>>>>>>>> second,
>>>>>>>>>>> which shows all the lights at the same brightness each time, I
>>>>>>>>>>> suspect
>>>>>>>>>>> the flicker is above 2000Hz.
>>>>>>>>>>
>>>>>>>>>> I once had an audio amplifier with a solar cell rather than a
>>>>>>>>>> microphone
>>>>>>>>>> for the input transducer. This made it possible to listen to
>>>>>>>>>> light.
>>>>>>>>>> The
>>>>>>>>>> sun is steady, incandescent lights (AC powered) hum.
>>>>>>>>>>
>>>>>>>>>> That was 40 years ago. Maybe something like that would work today.
>>>>>>>>>
>>>>>>>>> The trouble is I want to compare 2kHz+ from one light with 2kHz+
>>>>>>>>> from
>>>>>>>>> a neighbouring light and see if they're in sync.
>>>>>>>>
>>>>>>>> Maybe use a dual trace oscilloscope?
>>>>>>>
>>>>>>> Haven't got one unfortunately.
>>>>>>>
>>>>>>>> Since this landed in alt.home.repair, I gotta ask. Do you have
>>>>>>>> single-phase or two-phase?
>>>>>>>
>>>>>>> Single. I'm in the UK.
>>>>>> so 50 Htz - you can almost see an incandescent flicker at that
>>>>>> frequency (at 25 you could)
>>>>>>
>>>>>> (also rules out the previously mentioned "engineer friend")
>>>>>
>>>>> Lights flicker at twice the frequency, once for positive cycle, and
>>>>> once
>>>>> for negative cycle. LEDs only once unles using a bridge rectifier, or
>>>>> steady on using DC. Even though blinking they look normal straight on,
>>>>> my
>>>>> brain says something is wrong
>>>>
>>>> Some brains (or eyes) seem to be faster than others. I can easily (and
>>>> annoyingly) see flicker on CRT monitors below 90Hz, others don't even
>>>> see
>>>> the 50 or 60Hz ones. I can see flicker on 80% of car LED lights, others
>>>> don't see any. Designers really ought to account for those of us with
>>>> better eyesight.
>>>
>>> No point in doing that.
>>
>> There is when half the population is capable of seeing it.
>
> Half the population isnt.
Then you must know a lot of people with fucked eyesight.
>> Why only sell things suitable for those with shitty eyesight?
>
> They are actually designed to work fine for all but freaks.
Why would you call someone with better eyes a freak?
>> If you can't see the flicker that I can, then your eyes aren't as good as
>> mine.
>
> Nothing good about eyes that see flicker everywhere.
We see what is really there, you don't.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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