# Recent content by eng3

1. ### Temperature Coefficient of Resistance and Specific Heat

AH, I see, I must have missed that post. Now I'm only about 3X off from their estimate. A 3X safety factor seems resonable
2. ### Temperature Coefficient of Resistance and Specific Heat

It material is being heated electrically, it is a square plate in geometry. I thought that using my calculation using specific heat and then including losses from convection and radiation, I should arrive at an answer fairly close (ie. within 25%). However, the numbers I'm getting from the...
3. ### Temperature Coefficient of Resistance and Specific Heat

I am trying to estimate the amount of electrical power needed to heat up a material from 20C to 1000C in 20 seconds. Assuming it is 18sqin and 3mm thick, I used the specific heat which was given as 0.78 J/gC and weight 11.39g (from the destiny of 3.26). 0.78 J/gC x 11.39g x (1000C - 20C) /...
4. ### How to calculate blackbody temperature from radiance band?

I did see that, and that gives the temperature for one wavelength. My radiance is over a band. For example, in a BB calculator, I can put in 666.6K, over the 3-5um band, and it will give me 1000 W/m^2/sr How do I do the reverse? I have 1000 W/m^2/sr in the 3-5um and I want to calculate the...
5. ### How to calculate blackbody temperature from radiance band?

I know how to calculate blackbody radiance in a spectral band from a temperature by integrating (or summing) planks function. How can I do the reverse? For example, I have a Radiance of 1000 W/m^2/sr in the 3-5um band, I'd like to be able to calculate 666.6K.
6. ### How does Radiance change with a parabolic reflector?

So if I understand correctly, the area represents the projected aperture area? So in my example, I said I have a coil that is 1cmx1cm in area. The coil radiates 2 W/cm^2/sr. Lets assume spherically. With no reflector, the radiant intensity would be 2 W/sr? If I have a 10 sqcm (100% reflective)...
7. ### How does Radiance change with a parabolic reflector?

Lets say I have a coil that is 1cmx1cm in area that gets heat up. I am told that I get 2W/cm^2/sr output. So if I had 100 of them in an array, the total radiant intensity would be (2W/cm^2/sr x 100 x 1 sqcm =) 200W/sr. Now, let's say I add a parabolic reflector around each coil. How would I...