FLIR C3 User Manual

Theory of thermography
18
Figure 18.4 Blackbody spectral radiant emittance according to Planck’s law, plotted for various absolute
temperatures. 1: Spectral radiant emittance (W/cm
2
× 10
3
(μm)); 2: Wavelength (μm)
18.3.2 Wien’s displacement law
By differentiating Planck’s formula with respect to λ, and finding the maximum, we have:
This is Wien’s formula (after Wilhelm Wien, 1864–1928), which expresses mathematically
the common observation that colors vary from red to orange or yellow as the temperature
of a thermal radiator increases. The wavelength of the color is the same as the wavelength
calculated for λ
max
. A good approximation of the value of λ
max
for a given blackbody tem-
perature is obtained by applying the rule-of-thumb 3 000/T μm. Thus, a very hot star such
as Sirius (11 000 K), emitting bluish-white light, radiates with the peak of spectral radiant
emittance occurring within the invisible ultraviolet spectrum, at wavelength 0.27 μm.
Figure 18.5 Wilhelm Wien (1864–1928)
The sun (approx. 6 000 K) emits yellow light, peaking at about 0.5 μm in the middle of the
visible light spectrum.
#T559918; r. AN/42281/42281; en-US
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FLIR C3 Specifications

General

Temperature Range	-10°C to 150°C (14°F to 302°F)
Field of View	41° x 31°
Thermal Sensitivity	<0.10°C
Accuracy	±2 °C or ±2% of reading
Resolution	80 x 60 pixels
Image Storage	Internal memory
Connectivity	Wi-Fi
Display	3-inch touchscreen
Image Modes	Thermal, MSX, Picture-in-Picture
Digital Camera	640 x 480 pixels
File Format	JPEG
Battery Life	4 hours
Dimensions	125 x 80 x 24 mm (4.9 x 3.1 x 0.94 in)
Operating Temperature	-10°C to +50°C