|
|
| |
 |
|
| |
|
Glass thermometer - thermometer different types of contacts and the difference between Time :2009-07-2 |
|
|
|
|
ˇˇSource: thermometer, Alcohol thermometer, Bath thermometer,cartoon thermometer - Ningbo Yinzhou Hongxiang thermometer factory
1. LCD thermometer: recipes made with different liquid crystal, the phase transition temperature is different when the phase transition, the optical properties will change, so that appears to change the color LCD. If the different phase transition temperature of the liquid crystal coated on a piece of paper, the liquid crystal color changes, he will know why the temperature. The advantage of this thermometer is easy reading, but the disadvantage is that lack of precision, commonly used in fish tanks used in the watch to indicate water temperature.
2. Resistance thermometer: the resistance of the metal will increase with temperature, little change in temperature, its resistance and temperature is about a linear relationship in a larger temperature range, usually a simple quadratic polynomial can be used said. By measuring the resistance of the metal, he will know why the temperature. Such thermometers are usually made of platinum wire, may be accurate to 10-3 degrees C, commonly used in precision measurements. Due to the high melting point of platinum, so a greater measurable temperature range, at about -250 ˇć Celsius to about 1200 ˇć.
3. Gas thermometer: a fixed pressure, the density of the gas is not the size, and temperature into a linear relationship. Made use of this thermometer relations, called the constant pressure gas thermometer. Fixed volume, the density is not the gas, its pressure and temperature into a linear relationship. This relationship has made use of the thermometer, then known as the constant volume gas thermometer.
4. Rotating thermometer: thermometer rotation by a bimetal coil made of. Bimetal one end fixed, the other end connected to pointer. Sheet metal due to expansion of the two different levels, at different temperatures, resulting in double-metal coil in varying degrees, the resulting pointer refers to different dial positions, from the dial reading on the can know the temperature.
5. Semiconductor thermometer: changes in semiconductor and metal resistance of different temperature, the less resistance and greater range. Therefore a small amount of temperature change can also produce significant changes in resistance, the thermometer made of a higher degree of precision, often referred to as device temperature.
6. Thermocouple thermometer: thermometer thermocouple is two different metals connected by a voltage-sensitive components of the. Metal contact at different temperatures will be different at the two ends of the metal of the potential difference. Potential difference is very small, it takes into account the voltage sensitivity can be measured. By the voltage of the reading, he will know why the temperature.
7. Optical pyrometer measurements: if the high-temperature objects will be issued to a large number of visible light, they can use to measure the amount of heat radiation to determine its temperature, this thermometer is measuring optical thermometer. This thermometer is equipped with a red filter from the telescope and with a group of small bulbs, galvanometer circuit with variable resistor made. Use before the establishment of filament brightness corresponding to different temperature and current readings of the relationship. When used to test the telescope on the matter is, adjusting the resistance, so that the brightness of light bulbs with the same material under test, this time from the galvanometer will be able to read out the temperature of the material under test.
|
| |
| |
|
|
|
|
|
