What does PAR abbreviate from ?
In carpentry it means Plane All Round but what does it mean in this context
Parabolic Aluminum Reflector does not fit with the front positioned arrays
of high brightness LEDs.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

N_Cook wrote:
What does PAR abbreviate from ?
In carpentry it means Plane All Round but what does it mean in this context
Parabolic Aluminum Reflector does not fit with the front positioned arrays
of high brightness LEDs.


That`s simply a misnomer because 'ParCan' has become a catchall term for
that type of instrument - basically a headlamp in a tin can, cheap and
effective. The ParCan is the sledgehammer of theatre lighting
instruments - that`s not to say that they don't have their place.

In a true ParCan the lens and reflector are all part of the lamp, the
Can is just an inexpensive container.
Many people refer to fresnels as Pars, when in fact in true fresnel has
a separate reflector lens and lamp (bulb)

A Parnell is an instrument so called because it can mimic the light
output pattern of a parcan but which has separate lamp and reflector,
and an interchangable moulded fresnel type lens.

The only reason I can see for calling a led 'floodlight' a Par is
becuase they can be used in place of real parcans in some situations,
tho they have nowhere near the throw. Also the colour accuracy is very
poor compared with an incandescant lamp using a separate colour filter.

Ron(UK) wrote in message
...
N_Cook wrote:
What does PAR abbreviate from ?
In carpentry it means Plane All Round but what does it mean in this
context
Parabolic Aluminum Reflector does not fit with the front positioned
arrays
of high brightness LEDs.


That`s simply a misnomer because 'ParCan' has become a catchall term for
that type of instrument - basically a headlamp in a tin can, cheap and
effective. The ParCan is the sledgehammer of theatre lighting
instruments - that`s not to say that they don't have their place.

In a true ParCan the lens and reflector are all part of the lamp, the
Can is just an inexpensive container.
Many people refer to fresnels as Pars, when in fact in true fresnel has
a separate reflector lens and lamp (bulb)

A Parnell is an instrument so called because it can mimic the light
output pattern of a parcan but which has separate lamp and reflector,
and an interchangable moulded fresnel type lens.

The only reason I can see for calling a led 'floodlight' a Par is
becuase they can be used in place of real parcans in some situations,
tho they have nowhere near the throw. Also the colour accuracy is very
poor compared with an incandescant lamp using a separate colour filter.


Yesterday was the first time I was up close to one (of a pair) - used by a
pub-rock band. RGB plus white , sound modulated. It had been on for more
than an hour, running perhaps 50 or 60 percent LEDs lit ,on average. I bet
with myself how hot the can would be, and lost, after laying hand on the
can. I thought it would be higher , but only 10 or 15 degree C , at most,
over ambient.
Mentally summing how many closely packed high brightness LEDs in 8 inch disc
plus ps, no fan, and no vent holes - well the "music" wasn't enthralling.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On Sun, 13 Apr 2008 11:41:53 +0100, "N_Cook"
wrote:

What does PAR abbreviate from ?
In carpentry it means Plane All Round but what does it mean in this context
Parabolic Aluminum Reflector does not fit with the front positioned arrays
of high brightness LEDs.


Originally derived as an acrnyom for "parabolic aluminized reflector"

However, in today's world it is more a standard for shape and size.