Method of Measuring Dry-bulb temperature
Dry-bulb temperature can simply and inexpensively be measured by an alcohol-in-glass or a common mercury thermometer. It is the temperature recorded by using a conventional thermometer. The thermometer without muslin cloth in the psychrometer records dry-bulb temperature. It just reads the ordinary temperature of the air and is a measure of sensible heat content of the air. Its unit is degree C or kelvin (K).
When taking readings, the thermometer should be shielded from radiant heat sources such as motors, lights, external walls, and people. The reading must be taken in an area protected from these sources of radiation or thermometers must be shielded from radiant energy.
More sophisticated, hand-held thermistor, resistance bulb, or thermocouple thermometers can also be used. These are more expensive than a glass thermometer but are not necessarily more accurate. However these instruments provide digital reading and have advantages; for instance can be purchased with a probe allowing them to be used for measuring product or skin surface temperatures.