Re: Controlling Holiday Lights

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 28 Oct 2006 01:05:00 -0600, sylvan butler
<ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxxxxxxxx> wrote in message
<slrnek608s.vse.ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxx>:

>On Mon, 23 Oct 2006 23:48:07 -0400, Marc_F_Hult
<MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote:
>> On Mon, 23 Oct 2006 18:13:07 -0600, sylvan butler
>><ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>><slrnejqmkj.a3i.ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxx>:
>
>>>> (Q: Do incandescent lights flicker when run on 50 hz power?)
>
>>A:  No, because incandescent lights are very, very slow.
>
>>>Q:  Do fast acting lights (LEDs, fast phospher in fluorescent tubes,
>>>CRTs, LEDs, etc) flicker when run on 50hz power?
>
>> They do not turn on-off faster than the human flicker fusion frequency >>
which is what I wrote.
>
>But they do.  I and many others see the flicker from LEDs run on
>unfiltered 60hz A.C.  simply by turning ones head causing eyes to sweep
>past the LEDs.  Many people complain of this with LED christmas lights
>and night lights.

This is not how nor the conditions under which the human flicker fusion
frequency is conventionally determined. The fff  not a measure of fatigue.
Please read what I wrote.

>Fluorescent lighting phosphers are a bit slower, and the 120/sec
>flashing is much faster, but they also produce easily discernable
>flicker that bothers many people and is proven to exhaust eyes even for
>those people who are not consciously aware of flicker.

But 'exhausted eyes" are not a measure of the human flicker fusion frequency.
You are confounding a formally defined measure (at least it was when I took
psychology 35 years ago) with other vision-related phenomena.

But all this is silly. The point here was to assure than if we discovered that
your dimmer kinda sorta works  by skipping 1/2-cycles, you wouldn't claim that
to be acceptable performance.

... Marc
Marc_F_Hult
www.ECControl.org