User Guide

39
-2
0
-2
0
-10
0
+1
0
+2
0
+
30
+4
0
+
50
+
60
+7
0
+
80
+
90
°
C
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-10
Ω
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-10
-10
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TEMPERATURE-RESISTANCE
CORRELATION FOR HANNA PH
SENSITIVE GLASS
The resistance of glass electrodes partially
depends on the temperature. The lower the
temperature, the higher the resistance. It takes
longer time for the reading to stabilize if the
resistance is higher. In addition, the response
time will suffer to a greater degree at tem-
peratures below 10°C.
2x10
9
1x10
9
2x10
8
1x10
8
2x10
7
1x10
7
Since the resistance of the pH electrode is in
the range of 200 Mohm, the current across
the membrane is in the pico Ampere range.
Large currents can disturb the calibration of
the electrode for many hours.
For these reasons high humidity environ-
ments, short circuits and static discharges
are detrimental for a stable pH reading.
The pH electrode's life also depends on the
temperature. If constantly used at high tem-
peratures, the electrode life is drastically re-
duced.
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