CM probe English 2019/02 DK
CM - Corneometer
®
CM 825
CM 1 – Aim & Audience of this Manual
This manual contains the instructions necessary to work with the probe correctly and
in accordance with its intended use. The manual is meant to be read by the persons
who will be operating the probe.
It is only valid in context with the following instructions:
MPA Hardware and MPA Software or
MDD 4 or
Wireless Hardware and MPA Software
CM 2 – General Information on the
Measurement
CM 2.1 – Measurement Principle of the
Corneometer
®
CM 825
The measurement is based on capacitance
measurement of a dielectric medium, here the Stratum
Corneum, the uppermost layer of the skin. With
increasing hydration, its di-electric properties change.
The measurement is based on the fact that water has
a higher dielectric constant (81) than most other
substances (mainly < 7).
Gold tracks on
top of the in
the probe head, separated from the skin by a
glass lamina, build-up an electric field
between the tracks with alternating attraction.
One track builds up a surplus of electrons
(minus charge) the other a lack of electrons
(plus charge). When put on the skin surface,
the scatter field penetrates the very first layer
of the skin. The Corneometer
®
CM 825
measures the change in the dielectric
constant due to skin surface hydration
changing the capacitance of a precision
capacitor. The measurement can detect even
slightest changes in the hydration level.
Unlike the impedance measurement no
galvanic relation between the device and the measuring object and no polarization
effects exists.
CM 2.2 - Advantages of the Corneometer
®
CM 825
Substances on the skin (e.g. salts or residues of topical applied products) have
only minimal influence due to capacitance measurement.
It allows very quick measurement (1 s) important to avoid occlusion.
Continuous measurements over a longer time period can optionally be
performed.
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