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TCP TruDim dimmable CFLs


Travis Evans

Jan 1, 1970
Has anyone heard of these? They look quite interesting.

Spec sheet:

While the manufacturer doesn't appear to indicate whether these are less
prone to lifespan/electrode sputtering problems as other dimmable CFLs,
they do boast a number of performance improvements.

I ordered a couple of the 23-watt 1450-lumen 4100K ones, which I
received today. After performing the manufacturer-recommended 2-hour
"burn-in" at full power (actually, I ran them for about 6-7 hours just
for good measure), these are my first impressions after playing with
them for a bit:

* I'm not sure about the "dimming to 2%" claim. It's not clear what
exactly this "2%" figure refers to, but it doesn't appear to refer to
lumen output (or else the dimmest level should be about 29 lumens).
However, it does dim to a level that appears dimmer than a 40-watt
incandescent at full power, perhaps approaching that of a 25-watt
incandescent (rough guess). This should provide an adequate dimming
range for the majority of applications, I think. At this point, power
consumption is about 5-6 watts per lamp (around 30-35 VA at a PF of
around .33 (PF at full power is around .7)).

* The dimming curve does appear to be excellent. Many dimmable CFLs
don't change very noticably in brightness over the upper portion of the
dimmer control; these do. With a 100-watt incandescent operating on the
same dimmer beside a 23-watt TruDim CFL, the apparent brightness with
dimming appears to roughly match that of the incandescent, as claimed.

* While it's difficult to tell if the warm-up period is noticably
shorter than most other CFLs I've used, my wattage meter reveals the
operation of the "accelerated warm-up overdrive" feature, with wattage
consumption up to 30W over the first minute or two of operation before
settling back down to around 23-24W once the lamp has reached operating

* As claimed, I do not notice any 60- or 120-Hz flicker even at the
minimum brightness level as I do with other dimmable CFLs I've used.

* I like how they ramp up or down smoothly in brightness over about half
a second when the dimming control is adjusted quickly. I have some
Utilitech dimmable spirals bought at a local Lowes that tend to flicker
fairly wildly as the control is moved.

* The point at which the dimmer is adjusted too low and the lamps
extinguish and begin cycling is sharply-defined. In contrast, the
Utilitech and Sylvania dimmable CFLs I've used transition smoothly from
dimmed output to flickery end-only glow, making it a lot less
straightforward to determine where the "minimum safe dimming level" is.

I am a little bothered by the repeated cycling when the dimmer is
accidentally turned down too far. It seems like it would be better if
the electronics could detect this and stop trying to start the tube
after a couple of unsuccessful attempts.

So far, these seem like pretty nice CFLs with reasonable prices, as far
as dimmables go. Time will tell how well they do in the longevity area.