608-H2 TESTO, 608-H2 Datasheet - Page 2

• Manufacturer Part Number: 608-H2
• Description: HYGROMETER
• Manufacturer: TESTO

Specifications of 608-H2

• Humidity Range: 2% To 98%
• Resolution (°c): 0.1°C
• External Height: 120mm
• External Width: 89mm
• External Depth: 40mm
• Svhc: No SVHC (15-Dec-2010)
• Accuracy %: 2%
• Battery Size Code: 9V
• Operating Temperature Max: 70°C

Gas or air humidity measurements are
becoming more and more important.
Constant improvements to the technical
processes, higher demands on quality
and energy saving require an accurate,
stable and affordable measuring
procedure to measure air humidity.
Testo has succeeded in increasing the
range of applications for capacitive
sensors with the humidity sensor
developed here:
– Application temperatures to +180 °C
– Dew point measurement from -50 to
+100 °C
– Long-term measurement under
extreme conditions
– Highly accurate in the high humidity
range (>95%RH)
The outstanding characteristics of the
Testo humidity sensor are as follows:
– Precision
– Long-term stability
– Temperature resistance
– Robustness
Hair hygrometer
The hair hygrometer is
one of the oldest
methods used to
measure humidity. The
length of the hairs
changes in accordance
with the ambient
humidity. This change is
mechanically indicated as
relative humidity.
Advantages
– Simple to use
– Low cost applications
Disadvantages
– High maintenance
– Frequent regeneration
– Can be used only
– Highly inaccurate, not
– Slow measurements
measuring engineering
with low installation
costs
costs
of the hairs
from 15 % to 85 %RH
and up to max. 50 °C
definable
Psychrometer
A temperature probe
covered usually with a
damp cotton sleeve cools
down as a result of
evaporation. A second
temperature probe
measures the ambient
temperature. The ambient
humidity can be
determined from the
difference in temperature.
Advantages
– If used with care a
Disadvantages
– Cannot be used for
– Time-consuming
– Before every
very accurate
measurement of 2 to
3 %RH is possible
multipoint
measurements
handling (must be
moistened with
distilled water before
nearly every
measurement)
important
measurement, the
temperature must be
adapted to the
ambient temperature
and the sleeve should
be changed
Dew point mirror
A mirror is cooled until it
shows condensation after
having reached the dew
point temperature. The
condensation on the
mirror is monitored and
the dew point is then
measured.
Advantages
– Wide measuring range
– Highly accurate
Disadvantages
– Time-consuming,
– Not battery-operated
– Heavy (non-portable
– Highly accurate
– Slow adaptation time
– Large bench-top
expensive method
measuring instrument)
temperature
measurement required
instruments
Capacitive humidity sensor
A condensator changes its
capacity in accordance
with the ambient humidity.
Advantages
– Affordable, quick-action
– Wide measuring range
– Long-term stability
– Small, portable
Disadvantages
capacitive sensors were
regarded as unreliable
and unstable.
Today...
Testo`s capacitive sensor
has been tested
worldwide and has
established itself in
industrial measurement
engineering.
In the past...
and accurate
measurement (up to
±1%RH)
(0 to 100 %RH, -40 to
+180°C)
measuring instruments