Recent content by mhjerde

I can't say I'm too familiar with natural convection calculations. I managed a rough estimate of the surface area needed to dissipate heat for the prototype in an upright position, without really understanding all the intricacies of natural convection. It also turned out to be a bit on the low...

Does it make sense to try to use the chimney effect/stack effect to increase heat dissipation for a smallish electronic enclosure? I'm thinking that if I hollow out the two vertical ends of the enclosure, I can get a 100mm high 5x5mm "chimney" on each side. On paper I get about 0.09 Pa...

The emitter I plan to use has a 'viewing angle' of 120 degrees. The viewing angle is defined as 2\theta1/2, or 50% power angle. This is basically a lambertian emitter. 120 degrees is too wide. I want to narrow it into a 40 degree viewing angle. Light outside the camera field of view is lost...

I think I made a silly mistake. Looks like the right answer to the above is a focal length of 1.4 mm.

I'm building a light source for photography and I'm trying to calculate the focal length for a lens that will give me a 40 degree (full width) cone beam from a LED emitter. See attached image. [PLAIN]http://dl.dropbox.com/u/2301/LEDOpticDrawing.jpg The emitter itself measures about 0.5 x...