BulbCollector Forums
BULB DISCUSSION BOARDS => Christmas Lighting => Topic started by: geraldmusic on May 25, 2010, 11:41:06 pm
-
An electrical thing about which I am curious is ...
Why do I hear that the Sylvania fluorescent bulbs are not to be used with a DIMMER??
Curiously,
g
-
They're fluorescent, so they cannot be dimmed! :-D Only modern CFLs have dimming compatiblity as far as I know.
-
I don`t think that`s the reason. The old Sylvania "Fluorescent" decorative lamps are actually negative-glow lamps using neon and argon gas fills, and as far as I have been able to tell, green or blue phosphor coatings to generate the different colours. For example, the yellow ones use a predominantly neon (red-orange) gas fill with green phosphor. The orange one uses a neon fill with a plain white diffusing coating. The lamps are driven using simple wirewound resistors located in the bases, and at least using a Variac, they dim down to zero perfectly well.
I was not previously aware of the "no dimmers" rule, but can only imagine this refers to the simple two-wire triac dimmers intended for incandescent lighting. Those things usually do not work well with anything other than a resistive load, which the Sylvania lamps do not offer. That and the tiny power consumption, which is usually below the minimum load for those dimmers. If you had a long enough string of those lamps (to make the minimum load) and wanted to be able to dim them using a triac dimmer, I would imagine putting a single incandescent bulb in the string may offer enough of a resistive load to allow the dimmer to work at lower levels. A similar problem is encountered when trying to switch/dim LED light strings using some triac based controllers, and apparently the use of one "C7" 120 volt bulb in parallell with the string usually does the trick.
-
GREAT!
It's really good to know the answer.
The BAD news is that I have two recently-purchased Westek dimmers, one of which says "incandescent lamps only" and the other of which says "incandescent/halogen only."
:(
THANKS for the great detail!
-
Virtualy all domestic dimmers are marked "incandescent only" That is to stop people useing them for regular types of linear or compact flourescent lamp, most of which can not be dimmed.
A flourescent lamp that uses a resistance ballast (llike the ones disscussed) should be fine on such a dimmer, as noted above.
Owing to the very small loading of the Sylvania flourescents you will probably have to use an incandescent as well.
-
GREAT reply - T H A N K S !
So, in my 7-socket E12 string, I'll put in one garden-variety C7 lamp along with 6 of my resistance-ballast-ed Sylvania flourescents before patching it into my Westek dimmer.
Thanks AGAIN,
g