Справочник Пользователя для Hanna Instruments hi 931402

39

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 tempera-
tures below 10°C.

-20 -20

-10

0 +10+20 +30+40 +50+60+70 +80+90

° C

-10

-10

Ω

-10

-10

-10

-10

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 elec-
trode 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.

2x10

9

1x10

9

2x10

8

1x10

8

2x10

7

1x10

7