Parabolic and Elliptical Reflectors

DaveH

DaveH

Joined
Dec 2, 1999
Messages
12,249
What is the practical difference between a parabolic and elliptical reflectors as mentioned in the Carley lamp site?

I realize they are different conic sections/equations, does parabolic not need further focussing, while elliptical does?

when would I use one or the other?

Has anyone switched out their original reflector for one of Carley's? Looks like you'd need to use bi-pin lamps then too.

TIA,
DaveH
 
A parabolic reflector is unique in that it produces parallel rays of light. The reflector is constructed in the shape of a part of the parabola. If the light source is placed at the parabola’s focal center, rays striking the reflector bounce off parallel to one another. The result is a concentrated and harsh beam of light.

Moving the source away from the focal point and towards the reflector spreads the light. Moving it away from the focal point further from the reflector causes the light rays to converge.

The ellipsoidal is more efficient than the parabolic reflector. It is constructed in the form of half an ellipsoid. By mathematical definition, and ellipsoid has two focal points. The focal point nearest the reflector is called the primary focal point. The more distant focal point is called the conjugate focal point. If a light source is properly positioned at the primary focal point, the rays striking the reflector are redirected to converge through the conjugate focal point. Using this reflector, a large percentage of the light from the source is gathered into a concentrated beam.

Next weeks lesson; Lenses.


------------------
James Segura
San Francisco, CA

[This message has been edited by stjames (edited 06-24-2000).]
 
Thanks.

Next week? I have a Saturday morning class again.
smile.gif


DaveH
 
You must log in or register to reply here.
Back
Top