J
James D. Hooker
- Jan 1, 1970
- 0
I haven't cut open a Philips lamp yet, but if you look at some of the Osram
samples they don't seem to use a traditional tranformer. Seems to be more
like the switching unit you get in a dimmer switch which just chops up the
line voltage to limit lamp power. This sort of circuit is perhaps cheaper
and smaller than using a full electronic tranformer. Perhaps it also
explains why the luminous efficacy of these lamps is quite a bit lower than
the bare 12V capsules.
If we consider first that the 12V 20W IR capsule operates at 24lm/W, factor
in 5% absorption losses due to the second outer glass bulb, and then assume
a 90% efficiency for the "transformer", it indeed brings us down to a total
system efficacy of 20.5lm/W.
James
samples they don't seem to use a traditional tranformer. Seems to be more
like the switching unit you get in a dimmer switch which just chops up the
line voltage to limit lamp power. This sort of circuit is perhaps cheaper
and smaller than using a full electronic tranformer. Perhaps it also
explains why the luminous efficacy of these lamps is quite a bit lower than
the bare 12V capsules.
If we consider first that the 12V 20W IR capsule operates at 24lm/W, factor
in 5% absorption losses due to the second outer glass bulb, and then assume
a 90% efficiency for the "transformer", it indeed brings us down to a total
system efficacy of 20.5lm/W.
James