There are three kinds of temperature and humidity meters commonly used:

1.the electronic temperature and humidity meter determines the humidity according to the electrical conductivity of the humidity sensitive resistor or humidity sensitive capacitor at different humidity.

2.mercury or alcohol thermometer, the humidity is measured by a thermometer with double glass tubes, one of which has a volatilizer at the bottom, which should be provided with water during normal use to keep the evaporator moist. This kind of error is still very small, and the price is very cheap.

3. the dial thermometer works on the principle that two different metals have different degrees of expansion when the temperature changes.

Generally speaking, the electronic one is more accurate than that of the dial. The electronic household temperature and humidity meters all use thermal resistors and humidity resistors. The household-level temperature and humidity meters have an accuracy of ±1 ℃ and ±5% RH, while the dial is basically a hair hygrometer with poor accuracy and humidity of ±7% RH. look at the appearance and price when there is obviously no electronic visual selection of the readings, look at the sales volume and evaluation on Amazon, and then buy one you like.

After buying it back, because it is impossible to have professional calibration and identification equipment at home, so compare it with a mercury thermometer. The more accurate measurement of humidity is the dry bulb temperature and hygrometer, but there are few places to sell it, and the price is more expensive. Usually the temperature is very good to compare whether it is accurate, of course, the temperature and hygrometer technology is already very mature, basically do not have to worry about this kind of problem. if you're interested in digital thermometer hygrometer,follow us quickly,our website:www.lexinda.com.