Precision Hygro-Thermometer Psychrometer VS Aspirated Psychrometer

There is a clear difference between the Extech RH390 and RH490 precision Hygro-Thermometer Psychrometer versus an Aspirated Psychrometer


Aspirated Psychrometer

These units measure relative humidity using 2 thermometers, one dry and one wet (dew point). 
A reservoir of water is in the unit and a wick is attached to the wet bulb (dew point) thermometer. A small fan blows on both thermometers. The difference in temperatures determines the Relative Humidity either electronically or through a manual look-up chart using both bulb temperatures.

An aspirated Psychrometer measures Air Temperature and Dew point (wet bulb) temperature and computes Relative Humidity. These units are typically +/- 2% accurate.

 

Extech RH390 and RH490

The Extech RH390 and RH490 Measure Air Temperature and Relative humidity.The humidity sensor uses a capacitive sensor. The capacitive sensor accuracy is listed. The humidity sensor can be calibrated using the RH300-CAL calibrating salts.

These units measure Air temperature and humidity and computes the Dew point (wet bulb) temperature.

Views: 344

Reply to This

Photos

Loading…
  • Add Photos
  • View All

Members

Latest Activity

Sky Swendsboe posted a blog post

The Extexh HeatWatch HW30 365528

Hey Guys! Sorry for the looooooooooong hiatus.So my review today will be on the Extech HW30 Heat…See More
Monday
Sky Swendsboe posted photos
Monday
Vatche Arabian posted a blog post

Tools to Tackle Workplace Noise

June is National Safety Month. Today we’re looking at the hazards of excessive noise on the job.…See More
Jun 22
Jose González is now a member of Planet Extech
Jun 22

© 2015   Created by Vatche Arabian.

Badges  |  Report an Issue  |  Terms of Service