Table of Contents
- 1 Why do we use platinum wire and not any other metal in platinum resistance thermometer?
- 2 What are the limitations of a digital thermometer?
- 3 What is the accuracy of a platinum resistance thermometer?
- 4 What are the limitations of a thermometer?
- 5 What are some of the limitations of using an oral thermometer?
- 6 How do you find the sensitivity of a platinum resistance thermometer?
- 7 What are the disadvantages of platinum resistance thermometer?
- 8 What is the difference between gas thermometer and platinum thermometer?
- 9 Why can’t we use platinum as a temperature sensor?
Why do we use platinum wire and not any other metal in platinum resistance thermometer?
A platinum resistance thermometer (PRT) is a piece of platinum wire which determines the temperature by measuring its electrical resistance. The most reproducible type of sensor is made from platinum because it is a stable unreactive metal which can be drawn down to fine wires but is not too soft.
What are the limitations of a digital thermometer?
It is hard to determine how much power is left in a digital thermometer’s battery, which in turn makes it difficult to predict when it will die. Because they are specialised batteries, it is hard to locate replacements. And close-to-dying batteries will provide inaccurate readings.
What is the accuracy of a platinum resistance thermometer?
In general, PRTs can have high accuracy (0.01 °C), stability, and repeatability across a wide range of temperatures from -200 °C to 500 °C.
What are the advantages and disadvantages of platinum resistance thermometer?
Advantage: It has a wide range and is very accurate. It is best for small steady temperatures. Disadvantages: Unsuitable for rapidly changing temperature. Slow to respond.
Why platinum is selected for the construction of thermometer?
Definition: The platinum thermal resistance (PTR) uses platinum for determining the temperature. The thermometer measures the temperature over the range of 200°C to1200°C. The platinum is an unreactive metal and can easily be drawn into fine wires.
What are the limitations of a thermometer?
Drawbacks. Since they’re made from glass, mercury thermometers may break easily, allowing toxic mercury to escape. They may also cause cuts or glass splinters if they break. Since they contain a hazardous substance, mercury thermometers must be disposed of properly and can’t be thrown into the trash.
What are some of the limitations of using an oral thermometer?
Disadvantages: thermometers can break if bitten. inaccurate if client has just ingested hot or cold food or fluid or smoked. Disadvantages: inconvenient and more unpleasant for clients difficult for client who cannot turn to the side.
How do you find the sensitivity of a platinum resistance thermometer?
More simply stated, we can calculate the sensitivity of a resistance thermometer by multiplying the resistance of the RTD at the reference temperature R0 (i.e. its calibration temperature) by the Temperature Coefficient of Resistance (TCR, or alpha value) as follows: Sensitivity = KRTD = R0 * α.
Why the temperature above 1200 C Cannot be measured accurately by a platinum resistance thermometer?
Disadvantages of Platinum Resistance Thermometer The thermometer gives the slow response. The melting point of the thermometer is 1800° Celcius. But when platinum measures the temperature higher than 1200°C they start evaporating.
In what sense platinum resistance thermometer is a thermometer?
The thermometer measures the temperature over the range of 200°C to1200°C. The platinum is an unreactive metal and can easily be drawn into fine wires. Because of these properties of platinum, it is used as a sensing element in thermometer.
What are the disadvantages of platinum resistance thermometer?
THE RESISTANCE THERMOMETER (RTD) | |
---|---|
Advantage | Disadvantage |
the platinum resistance detector is stable and resistant to corrosion and oxidation | RTDs do not allow point measurement of temperature because of the dimension of the sensing element |
What is the difference between gas thermometer and platinum thermometer?
The temperature measurement through platinum resistance thermometer is easier as compared to the gas thermometer. The meter gives the precise reading of temperature. The thermometer has a wide range from 200 to 1200° Celsius. The thermometer is quite sensitive. The platinum has same resistance at the same temperature.
Why can’t we use platinum as a temperature sensor?
The resistance of platinum, like that of all metals is very low, so that a long wire is needed for the coil, which is bulky. This means that it takes a relatively long time to acquire the temperature of the surroundings, and also that it is unsuitable for use in measuring the temperature in confined spaces.
How to protect the platinum wire of a thermometer?
The platinum wire is protected by the stainless steel tube or by the glass coating. Glass or ceramic seal the sensing element. The sealing has two advantages. They provide the strength to the thermometer and protects the sensing element against the chemical reaction.
What are the disadvantages of platinum thermal resistance?
The platinum has same resistance at the same temperature. The following are the disadvantages of platinum thermal resistance. The thermometer gives the slow response. The melting point of the thermometer is 1800° Celcius. But when platinum measures the temperature higher than 1200°C they start evaporating.