XPost: uk.d-i-y, alt.home.repair
From: Gothberg"@internet.co.is
On Thu, 20 Dec 2018 21:25:45 -0000, % wrote:
> On 2018-12-20 1:56 p.m., William Gothberg wrote:
>> On Thu, 20 Dec 2018 20:40:26 -0000, % wrote:
>>
>>> On 2018-12-20 1:30 p.m., William Gothberg wrote:
>>>> On Thu, 20 Dec 2018 19:11:36 -0000, Rod Speed
>>>> wrote:
>>>>
>>>>> "William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
>>>>> news:op.zubnqbkho5piw3@desktop-ga2mpl8.lan...
>>>>>> On Thu, 20 Dec 2018 09:36:02 -0000, Jon Fairbairn
>>>>>> wrote:
>>>>>>
>>>>>>> "William Gothberg" <"William Gothberg"@internet.co.is> writes:
>>>>>>>> Agreed. All I can detect (with my digital camera) is that
>>>>>>>> one brand of LED light I have flickers about 5 times less
>>>>>>>> (not sure if it's smother or faster) than the others.
>>>>>>>
>>>>>>> Try a longer exposure and move the light rapidly relative to the
>>>>>>> camera.
>>>>>>
>>>>>> I wonder, if I fed the lamps with mains voltage DC, simply a bridge
>>>>>> rectifier and a huge capacitor, they'd reduce their flicker.
>>>>>
>>>>> Wont work at all if they use capacitor droppers and
>>>>
>>>> I made a few of those to power LEDs to indicate the function of my
>>>> central heating. I'm looking inside the flickery lamp just now (£15,
>>>> 20W). Without undoing the glue holding the PSU onto the inside of it,
>>>> all I can see is probably: the mains going through a large bipolar cap,
>>>> a tiny resistor (to discharge it safely?), a bridge rectifier, another
>>>> very large resister (to limit the LED current more accurately?), then a
>>>> 400V 4.7uF capacitor (which is bulged). A capacitor dropper with a
>>>> rectifier and smoothing capacitor after it? The one I made has no
>>>> smoothing cap, just mains to cap to resistor to bridge to LED. Perhaps
>>>> this bulged cap is why I'm getting flicker, I'll try replacing it
>>>> tomorrow.
>>>>
>>>>> they very likely do because those are the only cheap
>>>>> droppers for dropping such a large voltage.
>>>>
>>>> Aren't miniature SMPS units pretty cheap? I just bought a 12V 6A SMPS
>>>> for £4.50. Designed for powering LEDs - but I've looked inside it and
>>>> it's definitely a switched mode, not a capacitor dropper. Now this
>>>> flickery LED lamp I'm looking inside, it's about 20W, so 12V at 2A is
>>>> all that's required, it could have had an SMPS in it similar to the one
>>>> I just described.
>>>>
>>>> I'm now looking inside one of the better LED lamps (the non-flickery
>>>> model). It has a basic SMPS inside it. They're 9W and £4 each for the
>>>> whole lamp. I'm sure it's more than just a standard SMPS though,
>>>> because when some LEDs fail short circuit (it has about 40 in series),
>>>> the voltage coming from the PSU drops, to maintain the correct current
>>>> for the remaining good LEDs.
>>>>
>>>>> Very easy to try tho and see if it works.
>>>>
>>>> Looks like it would help the better ones, but not the crap one. Better
>>>> (as I only have a few crap ones) to stick a bigger smoothing cap inside
>>>> those. For the good ones, the only problem I can foresee with the
>>>> external smoother, is overloading the lamp's bridge rectifier, as it
>>>> will only be conducting on two of the four diodes.
>>>>
>>>>>> The cheap shit LED lamp I have that actually flashes at 100Hz would
>>>>>> most
>>>>>> likely get much brighter and burn out, so I'd have to adjust that,
>>>>>> but the
>>>>>> others which only flicker 8% would just get 4% brighter.
>>>
>>> you could use being 4 % brighter
>>
>> That would make my IQ 140.
>>
>> Was the above too difficult for you to discuss?
>
> I Q's are the lamest oldest forgotten tests of them all ,
You're just jealous.
> are you excited this is going to be how usenet is for you for the next
> 20 - 30 years
Be more specific.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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