Halogen
PAR
lamps
are
lamps
within
lamps.
A
small
halogen
capsule
is
mounted
and
sealed
inside
a
PAR
bulb
as
shown
in
Figure
8.11,
and
thus
the
advantages
of
halogen
efficacy
and
long
life
are
combined
with
beam
control
from
the
PAR
shape.
Precise
ConstantColor
Lamps
Precise
lamps
as
shown
in
Figure
8.12
are
very
small.
They
are
available
in
two
sizes:
The
lamps
are
rated
at
12
volts
and
need
a
transformer
to
reduce
the
normal
240V
to
12V.
Wattages
range
from
12
to
75W
and
the
range
of
beam
spreads
is
from
7
to
55
degrees.
The
lamp
caps
are
all
2
pin
(GU4
for
MR
11
and
GU5.3
for
MR
16).
They
are
available
as
open
reflectors
or
with
a
front
cover
glass.
The
life
of
MR11
lamps
is
3500
hours
(2000
hours
for
12W).
The
life
of
MR16
lamps
is
4000
hours
for
all
ratings
except
50W
which
has
5000
hours
life.
The
open
reflector
version
should
be
used
in
enclosed
luminaires.
Figure
8.12.
Precise
ConstantColor
lamps.
ConstantColor
dichroic
coating
provides
consistent
colour
quality
and
long
life.
-
Consistent
white
light.
-
No
discoloration
at
the
beam
edges.
-
No
discoloration
of
the
reflector.
-
No
fringe
colours.
-
No
lumen
loss
due
to
coating
discoloration.
-
50W
versions
have
6000
hour
life.
-
Cool
beam
with
over
60%
of
IR
radiation
transmitted
backwards
through
the
reflector.
