When you are working in an industrial environment
or with things that you cannot or do not
want to get close enough to measure with
a contact thermometer, an infrared thermometer
can give you a very accurate reading from
a distance. Infrared thermometers essentially
work the same way as light meters, though
in a wavelength that is not visible to the
human eye. Things that emit heat radiate
it through infrared emissions; the brighter
the object in the infrared spectrum, the
hotter it is.
When looking for an infrared thermometer,
the features to consider are:
- Temperature range - Generally, the thermometers
can read temperatures from below zero (Fahrenheit)
to several hundred degrees above it. Wider
ranges are available if you need to work
with frozen gases or molten steel.
- Accuracy - Almost any instrument will work
if you are only interested in a reading within
a few degrees of the actual surface temperature
of the object you are measuring. More accurate
meters can have errors well less than a degree
and be used for clinical measurements of
people.
- Distance to object - How far away you can
measure the temperature of an object depends
on the degree of focus of the pickup lens.
The greater the temperature extremes you
work with, the greater the distance to object
capability you will want.
- Weight and size - Most thermometers look
and handle like a gun. That is very convenient
for pointing, but usually carries a penalty
of a pound or two in weight. Extremely lightweight
models may be no larger than a several ounce
small flashlight and fit in your front shirt
pocket.
- Targeting beam - Many infrared thermometers
have a laser pointer built into them that
allows you to see exactly what you are pointing
at. A must if you have a narrow focus meter
and work at some range from your subject.
- Reading hold - Many infrared thermometers
allow you to capture a reading into memory
and hold it for display. Perfect for places
where you want to get in, make a reading,
and get back out.
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