From: don@manx.misty.com (Don Klipstein)
Newsgroups: misc.consumers.frugal-living misc.consumers misc.consumers.house
Subject: Re: Compact fluorescents slow to reach full intensity
Date: Sun, 11 Mar 2007 02:12:41 +0000 (UTC)

In article , Jeff wrote:
>Tim Smith wrote:
>
>> In article <1173278931.621490.121930@s48g2000cws.googlegroups.com>,
>>  trader4@optonline.net wrote:
>> 
>>>I haven't seen one yet that didn't have a significant difference in
>>>output for many seconds after being turned on, including the ones that
>>>say they are quick start.   In my experience, the quick start ones are
>>>better, but there is still a significant delay of maybe 30 secs or
>>>more in reaching full output.  And it's worse in cold applications.
>>>It's also possible that people thinking they reach full output right
>>>away just aren't paying close attention.   If you turn one on, take a
>>>look at it initially and then again at 2 mins.
>> 
>> 
>> I don't see a difference, but if I hook up in series some batteries, a 
>> resistor, a photoresistor, and a current meter, and put the 
>> photoresistor under a CFL and turn it on, I can see the current is 
>> indeed going up over 30 secs or so, and so, presumably, the light is 
>> going up.
>
>The eye is logarithmic. In photography, one stop is twice the light and 
>the smallest increment that photographers are concerned with is 1/3 of a 
>stop. That's a much larger change that what you were measuring.
>
>   Jeff
>> 
>> With one of my lights, the current in the aforementioned circuit started 
>> at 0.36 milliamps, and rose to 0.40.  With another light, it started at 
>> 0.34, and rose to about 0.38.  (The photoresistor was not at the same 
>> distance from the lights, and they were not the same brand of light, nor 
>> the same color, so such variation between the two is not surprising).

  I think Tim Smith made a poor choice of resistor values.  I would have 
tried no fixed resistors at all, just the photoresistor.  My experience 
is that compact fluorescents start with eyeball estimate 20-35% of their 
full light output when the arc is first fully established.  Ones with 15 
mm tubing tend to do better in this area in my experience, starting close 
to half brightness.  But few CFLs have this, and many that do are by 
Lights of America, and I have personally experienced more than a fair 
share of problems with that brand.  Thankfully CFL torchieres often have 
this tubing size.

 - Don Klipstein (don@misty.com)