Extech - Sensors & Sensibility: Inside Thermometers, Hygrometers and Thermo-Hygrometers

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By Andre Rebelo

Temperature and humidity. These two parameters are tremendously important variables in an unimaginable array of applications. It's no wonder that Extech has so many different meters to track one or both of these variables. We have heard from customers ranging from a sweets confectioner who needs chocolate to stay at the right temperature to make candies to a helicopter assembly plant that developed an emergency response plan when static hazards were present.

If you need to measure temperature or humidity, think about what's inside the meters you're considering, particularly the sensors.


For humidity, there are two types of humidity sensors found in today's hygrometer/psychrometer market: capacitive and resistive. Be sure you select a hygrometer with a capacitive sensor. This type of sensor will offer the best accuracy, and will improve the meter's accuracy overall.

There are also humidity meters with resistive sensors. Generally, these suffer in accuracy without a trade for some other advantage. For a number of years, Extech has opted for capacitive sensors which means better accuracy and better meters for our customers. Be sure to ask about which type of sensor is inside a hygrometer before clicking "Buy" or heading to the checkout counter.


Temperature meters, or more commonly called thermometers, are probably the most ubiquitous test instruments in the world and in history - second to clocks or chronometers perhaps. In many applications, a few degrees of deviation can mean quality problems in a production line, failed crops, or could signal a fatal hazard for farmers or summertime athletes.

You can see the importance of temperature measurements in Extech's catalog. We carry many, many different models suitable for different jobs. Because temperature is so pervasive, you'll also find temperature capabilities built into a wide range of meters that you wouldn't expect to measure temperature...

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