PCE-555 hygrometer
handheld, pocket-sized hygrometer, measures humidity, temperature,
dew point and wet bulb globe temperature

This hygrometer is designed to take quicker measurements of humidity and temperature. The PCE-555 hygrometer also offers a calculation of dew point and information about wet bulb globe temperature. This allows elimination of fungus in food storage, as well as in food transportation. It is also very useful in the construction industry to determine condensation in walls. Thanks to its solid design, this hygrometer is ideal for taking measurements on site, so long as the humidity sensor is not touched, manipulated or placed directly into liquid as it is a very sensitive component.

This table perfectly illustrates the connection between dry bulb temperature, wet bulb temperature and relative humidity. This link shows another hygrometer, which is superior to this model,  with the ability to be recalibrated with two humidity standards. Here you will find an overview of all our hygrometers. 

PCE-555 hygrometer

Measurement ranges

0 to 100% r.h.
-30 to 100°C

Resolution

0.01% r.h.
0.01°C

Accuracy

±2.0% r.h. at 25°C
±0.5°C at 25°C

Display

dual LCD with 4.5 positions

Battery

9 V battery (PP3)

Dimensions

225 x 45 x 34 mm

Weight

200 g

Examples of use for the PCE-555 hygrometer

With the PCE-555 hygrometer you can measure ambient conditions including humidity in the top portion of the LCD and temperature shown on the bottom and it also calculates wet bulb temperature and dew point, which are useful for calculating thermal stress. There is a small video to the right which shows the device measuring humidity and temperature. This link shows another hygrometer which can measure relative humidity, temperature, calculate dew point and it has memory for storing readings. We also have another type of hygrometer which can measure relative humidity, temperature, calculate dew point and also measure absolute humidity with a sensor.

Dry bulb temperature is simply the environmental temperature. It's the temperature that is measured using any kind of thermometer.
Wet bulb temperature is determined by using a mercury thermometer which is situated in the shade with the bulb covered with a piece of wet fabric under a current of air, measuring, for example, a vent or a rotating electric fan. In this way, the evaporation of water absorbs heat lowering the temperature, reflecting the decrease in the temperature reading. The lower relative humidity is, the quicker the water in the fabric will evaporate and the further the resulting decrease with respect to the dry bulb temperature (this is used to give an idea of thermal sensation).
Dew point is the temperature at which air vapour turns into condensation, producing dew, mist or frost if the temperature is low enough.
This link has more information about temperature and the most common units of measurement in the international system of measurement relating to temperature.

Wet bulb definition

If we pay attention to the wet thermometer temperature (wet bulb temperature), the same wet bulb temperature is always obtained with different temperature and relative humidity combinations: for instance, the same wet bulb temperature is obtained 10ºC for 20ºC and 23% Hr or for 15°C and  52% Hr, as well as many other combinations which are shown in the table for humidity meters. This fact is very important for the operation of conditioning installations due to the fact that the air which is located can be converted into one state or another without power supply. Taking into account an air mass at  20°C to 23% Hr and transforming water in water vapour without any external power supply, relative humidity increases at the same time that temperature decreases owing to the evaporation cold. All the states obtained during the evaporation process are near the line of the constant wet bulb temperature: at 52% Hr a 10°C temperature is reached. These changes are called adiabatic and are valued in the conditioning technique.

Contact:
PCE Instruments UK Limited
Units 12/13 Southpoint Business Park
Ensign Way, Southampton
United Kingdom, SO31 4RF
Phone: +44 ( 0 ) 2380 98703 0
Fax: +44 ( 0 ) 2380 98703 0

Below you will find an overview of the different product groups of measuring instruments