RTD
- 1. Resistance Temperature Detector Made by- Bhavesh Mishra STUDENT AT JSSATEN DEPARTMENT OF IC
- 2. What is an RTD? ⢠RTD stands for Resistance Temperature Detector. ⢠The change in temperature is detected by the change in resistance of the wire. ⢠There are two types of RTD: 1. Having positive thermal coefficients of resistivity (resistance increases with the increase in temperature respectively). 2. Having negative thermal coefficients of resistivity (resistance decreases with the increase in temperature respectively).
- 3. ⢠RTDs are used for temperature measurements by using them in bridge circuits. ⢠The change in temperature causes considerable resistance change which gives a voltage drop in accordance with the thermal coefficient of resistance of the wire. ⢠This voltage is further amplified and the temperature is read thus.
- 4. This is how the RTDs are used in circuits assisting in automatic control and measurement with high accuracy.
- 6. RTD PROBE
- 7. Common Resistance Materials for RTDs: ⢠Platinum (most popular and accurate) ⢠Nickel ⢠Copper ⢠Balco (rare) ⢠Tungsten (rare)
- 8. Advantages ⢠Due to no fluid present absolute temperature is recorded. ⢠It is highly sensitive and gives accurate results. ⢠It has a good range of temperature measurement. It can thus measure from very low to very high temperature. ⢠Due to electrical output (resistance change) it can be used with PLCs and complete automation can be achieved.
- 9. Applications of RTD ⢠It is widely used in furnaces for automatic temperature measurement. ⢠Due to its compactness, it replaces conventional thermometers as well as thermocouples thus eliminating the use of lots of wires. ⢠Used in medical and chemical laboratories to detect very low temperatures (like dry ice and liquid nitrogen). ⢠Due to electrical output it is used wherever feedback system is required and corrective action is thus taken in an automated system.
- 10. Questions And Answers ⢠Why use an RTD instead of a thermocouple or thermistor sensor? ⢠Each type of temperature sensor has a particular set of conditions for which it is best suited. RTDs offer several advantages: ⢠A wide temperature range (approximately -200 to 850°C) ⢠Good accuracy (better than thermocouples) ⢠Good interchangeability ⢠Long-term stability With a temperature range up to 850°C, RTDs can be used in all but the highest-temperature industrial processes. When made using metals such as platinum, they are very stable and are not affected by corrosion or oxidation. Other materials such as nickel, copper, and nickel-iron alloy have also been used for RTDs. However, these materials are not commonly used since they have lower temperature capabilities and are not as stable or repeatable as platinum.
- 11. Why is platinum more commonly used? ⢠The RTD wire is a pure material, typically platinum. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile(Easily breakable), they are often housed in protective probes.
- 12. Thank YOU