How Pawkit Works; Accuracy; Getting Started; Components Of Your Pawkit System - Decagon Devices pawkit Operator's Manual

How Pawkit Works

The Pawkit uses a capacitance humidity sensor to measure
the water activity of a sample. The sensor is suspended in the
headspace of the chamber and uses a special polymide mate-
rial sandwiched between two electrodes to sense humidity
changes. The sensor converts the humidity value into a spe-
cific capacitance, which is then measured electronically by
the circuit. 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
this accuracy is more than adequate. If you require higher
accuracy in your measurements, we recommend you use
Decagon's AquaLab water activity meter, which is a lab-
grade, bench-top instrument that has an accuracy of ±0.003
a
, and measures based upon the chilled-mirror dewpoint
w
method. Contact Decagon for more details.

Getting Started

Components of your Pawkit System:

Your Pawkit should have been shipped to you with the fol-
lowing items:
• Pawkit main unit
• Durable carrying case
Pawkit User Manual
2. About the Pawkit
a
. For many applications,
w
5