Decagon Devices Pawkit, Руководство оператора

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Pawkit
About the Pawkit
5
2. About the Pawkit
The Pawkit is designed to be a simple, rapid and
portable system for measurement of water activity.
It is easy to use, durable, and requires little mainte-
nance.
How Pawkit works
Pawkit uses a dielectric humidity sensor to measure
the
a
w
of a sample. In an instrument that uses this
technique, a special porous polymer is placed
between two porous electrodes in the headspace of
a sealed chamber. The electrical properties of the
polymer change depending on the relative humidity
of the chamber. The electrodes give a signal based
upon the relative humidity in the closed chamber.
This signal is then translated by the software and
displayed as water activity on the instrument’s
screen. At equilibrium, the relative humidity of the
air in the chamber is the same as the water activity
of the sample.
Accuracy
The Pawkit is accurate to ±0.02
a
w
. For many appli-
cations, this accuracy is more than adequate. If you