Milwaukee Instruments SONAR MA917B/1 Manual De Usuario
The pH electrode, due to the nature of its construction,
needs to be kept moist at all times. In order to operate prop-
erly, glass needs to be hydrated. Hydration is required for
the ion exchange process to occur. If an electrode should
become dry, it is best to place it in some tap water for a half
hour to condition the glass.
pH electrodes are like batteries; they run down with time and
use. As an electrode ages, its glass changes resistance.
This resistance change alters the electrode potential. For
this reason, electrodes need to be calibrated on a regular
basis. Calibration in pH buffer solution corrects for this
change. Calibration of any pH equipment should always
begin with buffer 7.0 as this is the "zero point." The pH scale
has an equivalent mV scale. The mV scale ranges from
+420 to -420 mV. At a pH of 7.0 the mV value is 0. Each pH
change corresponds to a change of approx. ±60 mV. As pH
values become more acidic the mV values become greater.
pH electrodes have junctions which allow the internal elec-
trolyte solution of the measuring electrode to leak out into
the solution being measured.
pH Electrode
basics
pH Electrodes
7
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Model
MA916B/1 - MA916B/3
MA917B/1
MA918B/1
Measuring Range
0 to 13 pH
0 to 14 pH
0 to 12 pH
Temperature Range
-5 to 100°C (23 to 212°F)
0 to 100°C (32 to 212°F)
-5 to 100°C (23 to 212°F)
Shaft Material
glass
glass
glass
Reference Electrolyte
KCl 3.5M + AgCl
KCl 3.5M
KCl 3.5M + AgCl
Reference Junction
ceramic, single
ceramic, single
ceramic, triple
Reference Type
single, Ag/AgCl
double, Ag/AgCl
single, Ag/AgCl
Shape of membrane
spheric
spheric
conic
Max pressure
0.1 bar
0.1 bar
0.1 bar
Connector Type
BNC
BNC
BNC
Cable length
coaxial, 1 or 3 m
coaxial, 1 m
coaxial, 1 m
Shaft length
120 mm
120 mm
120 mm
Diameter
12 mm
12 mm
12 mm
Application
laboratory applications
laboratory applications
laboratory applications
Glass Conic Tip Sensor
Glass Spheric Sensor
Epoxy Electrode
M
A918
B /1 =1 m
M
A917
B /1 =1 m
M
A916
B /1 =1 m
/3 =3 m
12 mm
120 mm
12 mm
120 mm
12 mm
120 mm
MA916B/1 (will be
replaced by SE100)
replaced by SE100)