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: 275

Reply to This

Photos

Loading…
  • Add Photos
  • View All

Members

Latest Activity

Kevin Olson is now a member of Planet Extech
yesterday
Profile IconVincent Dagastino and Ralph joined Planet Extech
Dec 1
Doris Klein's photo was featured
Nov 19
Doris Klein posted a photo
Nov 11

© 2014   Created by Vatche Arabian.

Badges  |  Report an Issue  |  Terms of Service