Candelabra bulbs are in some of the most lighting-sensitive areas of the house — often in a chandelier-type fixture in the entry or in the dining room — where high-CRI is important. And, since the dinning room is the one room that is most likely to have a triac-dimming switch, candelabra bulbs benefit most from dimmability. Cree’s 5W, 40W-equivalent candelabra E12-base bulb targets this market with its dimmable 90+CRI light.
The bulb makes clever use of an internal plastic light guide which you can see in the center of the bulb here:
The centered plastic light guide stops abruptly before reaching the top of the bulb, yet when it’s illuminated, the light continues all the way to the top:
A very clever use of a light guide and internal reflections.
Take a look at a how this works in real time in this video:
Even when turned off, the Cree is good looking. In case you aren’t familiar with other LED candelabra bulbs, here’s an older one:
Whether off or on, it’s kind of ugly; The Cree’s appearance is a big improvement.
Cree Light Spectrum
Below is the Cree’s spectral power distribution, showing its very nice 92 CRI. It makes a noticeable difference to have high-CRI bulbs at the dining room table.
It turns out that it’s not very difficult to get the bulb lens/cover off — it sort of snaps into place and is easily un-snapped. (This is not something you should do because of the exposed voltages; it also voids the warranty.)
Here’s a still from the above video with the dimmer switch on low, and the camera stopped way down so that we can photograph the light within the bulb:
With the cover off — the tip of the light saber vanishes:
…showing that the reflections within the plastic cover are responsible for the full light pattern.
And with the cover removed:
…we see that there’s just a single LED component producing the light. Without the light guide and cover, the bulb can’t do it’s job.
Compare the Cree to the old-style LED candelabra:
The old bulb on the left has a total of 18 LEDs on that pedestal (4 on each side, plus two on the top) while the Cree just has one large LED, pointed straight into the light guide.
A Single LED Provides All the Light
I don’t see this 5mm-square LED in the Cree portfolio, but we can learn a little bit about it when the cover is off. The photo on the left below shows the LED all the way off. When it’s just slightly on, we can see that it’s really an array with four separate sections. The voltage across the LED varies from 45V (barely on) to 59V (full-on).
Compared to the Cree 4Flow or the TW-series T8 lamp, this candelabra bulb has very sturdy packaging in the form of an aluminum enclosure. The LED and its pc board are thermally glued to a top plate which is press-fitting into the metal base, which is in turn enveloped by the plastic casing:
Inside the base, there’s just a single pc board:
Here’s a closeup of what appears to be the power control IC:
…which reads BP3211; 14C32A; AUF04. I don’t know what IC this is.
Anyone know? [UPDATE: See comments below: It looks like the BP3211 from Bright Power Semiconductor. Thanks, Dave.]
Cree candelabra bulb specs:
Color Temperature (CT): 2700
Color Rendition Index (CRI): 90+
Power Factor: .95
In summary, this is a great candelabra light, and I’m replacing my old-school candelabra LEDs with it. It’s also available in a 25W-equivalent (200lm) version. It’s currently sold only at Home Depot; both versions are 3 for $20.