1. What temperatures do infrared thermometers measure? A non contact infrared thermometer measures surface temperature.
2. How does an infrared thermometer work? A non-contact infrared thermometer measures thermal radiation emanating from a surface. The thermal energy detected is converted into a surface temperature reading.
3. Can an infrared thermometer measure air temperature? No, an infrared thermometer can only measure objects or targets that are opaque. However, room temperature or air temperature can be monitored indirectly by measuring the surface temperature of an object in thermal equilibrium with the surrounding air, such as leaves on a tree outside or furniture upholstery indoors.
4. Does the laser from an infrared thermometer interact with the surface to measure temperature? No, the laser on an infrared thermometer is used only for aiming the non contact thermometer at a surface.
5. What is D:S ratio or distance-to-spot size ratio mean? Every non contact infrared thermometer has optics that define the IR thermometer's field-of-view. For example a “distance to spot size ratio” (or D:S ratio) defines the area measured by the IR gun. For example, a D:S ratio of 10:1 means if you are measuring an object’s temperature from a distance 10-inches away, the IR gun will be measuring temperature over a “measurement circle” of about 1-inch in diameter. Likewise, if you are 10-feet from an object, the IR gun will measure temperature over a circle about 1-foot in diameter. There is no measurement distance limitation, but the object’s size must always be slightly larger than the “measurement circle”.
6. How does the laser help aim a non-contact infrared thermometer? A non-contact infrared thermometer with a single laser illuminates the center of the "measurement circle", whereas a dual-laser non contact infrared thermometer illuminates the diameter of the measurement circle.