PASCO TD-8580A Thermal Cavity - Manual (Page 7)

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Model No. TD-8580A Sample Data
7
Sample Data
DataStudio files containing these data can be found on the included CD-ROM.
Infrared Light Intensity versus Temperature
The graphs above show I versus T (above left) and I
versus T
4 (above right) for the black surface. The
curve fit applied to I versus T is ; note
that the curve intersects the horizontal axis at
, the approximate temperature of
the sensor.
The graphs of I versus T for the different surfaces of
the cube (right) show that the black and white surfaces
have similar emissivities in the IR region of the spec-
trum, and the emissivity of the polished surface is
much lower.
Reflected Visible Light and Emitted Infrared Light
These graphs show visible light intensity versus posi-
tion (top right) and IR light intensity versus position
(bottom right) at 92 °C. In the visible region of the
spectrum, the cavity is darker than the surrounding
cube surface; in the IR region the cavity is brighter.
Resistance to Temperature Conversion
To find the temperature (T) measured in kelvin based on the resistance ( R ) of the
embedded thermistor measured in k Ω , use the formula:
I A T
n
× B + =
T 294 K 21 ° C = =
1
T
--- A B
R
10
------
 
 
ln ⋅ C
R
10
------ ln
 
 
2
⋅ D
R
10
------ ln
 
 
3
⋅
+ + + =