4
PRINCIPLE OF OPERATION
Absorption of light is a typical phenomenon of interaction between electromagnetic radiation and matter.
When a light beam crosses a substance, some of the radiation may be absorbed by atoms, molecules or
crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length through the
matter and on the physical-chemical characteristics of substance according to the Lambert-Beer Law:
-log
I
/
I
o
=
ε
λ
c d
or
A
=
ε
λ
c d
PRECISION AND ACCURACY
Precision
is how closely repeated measurements agree
with each other. Precision is usually expressed as
standard deviation (SD).
Accuracy
is defined as the nearness of a test result to
the true value.
Although good precision suggests good accuracy, precise
results can be inaccurate. The figure explains these
definitions.
For each method, the precision is expressed in the
related measurement section.
SPECIFICATIONS
Light Life
Life of the instrument
Light Detector
Silicon Photocell
Environment
0 to 50 °C (32 to 122 °F);
max 90% RH non-condensing
Power Supply
External 12 Vdc power adaptor
Dimensions
235 x 212 x 143 mm (9.2 x 8.34 x 5.62")
Weight
1.5 Kg (3.3 lb)
For specifications related to each method (e.g. range, resolution etc.) refer to the related measurement
section.
