RH390-EU-EN V2.2 2/11
2
Introduction
Congratulations on your purchase of the Extech RH390 Digital Psychrometer.
This device measures Humidity, Air Temperature, Dew Point temperature and
Wet Bulb temperature. Advanced features include Data Hold, Auto Power Off,
and MAX/MIN reading. Careful use of this meter will provide years of reliable
service.
Specifications
Function
Range and Resolution
Accuracy
Humidity
0.0 to 100.0%RH
±2%RH (20% to 90%)
±3%RH (10% to 20% and 90 to 95%)
±4%RH typical at 1% and 99%
Temperature
-20 to 70
o
C
(-4.0 to 158.0
o
F)
±1
o
C (±1.8
o
F)
-30.0 to -19.9
o
C
and 70.1 to 100.0
o
C
(-22.0 to – 3.9
o
F
and 158.1 to 199.0
o
F)
±1.5
o
C (±2.7
o
F)
Display
Dual LCD
Response Time:
<30 seconds (90% of final value in moving air)
Sensor Type
Humidity: Precision capacitance sensor
Temperature: Thermistor
Wet Bulb
0 to 80°C (32 to 176°F) (calculated from RH and Air
temperature measurements)
Dew Point
-30 to 100°C (-22 to 199°F) (calculated from RH and Air
temperature measurements)
Operating Conditions
0 to 50
o
C (32 to 122
o
F); < 80% RH non-condensing
Storage Conditions
-40 to 85
o
C (-40 to 185
o
F); <99% RH non-condensing
Power Supply
9 Volt battery
Battery Life
Approx. 24 hours
Dimensions / Weight
200 x 45 x 33mm (7.8 x 1.7 x 1.3”); 200g (7 oz.)
