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.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.
> Why only sell things suitable for those with shitty eyesight?
They are actually designed to work fine for all but freaks.
> 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.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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