For certain industries and functions, having exact temperature measurements is an absolute must. The temperature gauges must be able to read small changes in temperature. Needing exact readouts is important, but it is not simple to achieve. Currently, on the market there are three mainly used measuring devices. These include:
- Thermocouples
- RTDs
- Thermistors
Each device has its own benefits and downfalls, and so it is important to weight the differences between the three. Knowing the advantages and drawbacks will help you pick a measurement tool is most suitable for the work being done. Each of the three shares the same basic operation principles, but give a different output. Each of the measuring tools is:
- Stable
- Accurate
- Sensitive
- Responsive
Knowing the measuring rates you'll need, the accuracy, as well as the response time will help you pick the best possible measuring device. If you do not know the answer to the above question, you must figure it out because it should be the basis for the type/kind of measuring device.
Thermocouples: these devices are made in many different configurations. They create small voltage signals that give temperature readouts. Dissimilar metals meeting at a junction create the voltage. Within the field of thermocouples, there are eight common types of calibration groups. This includes T, S, B, E, J, E, K, and R). Each of the different groups has it own characteristics and ranges.
Thermocouples have their benefits and drawbacks.
Pro
- Different sizes/configurations
- Inexpensively priced
- Quick Response
Con
- Medium sensitivity
- Medium accuracy
- Low Signal Strength
Thermistors: These resistors are rather similar to RTDs. The main distinction is the use of semiconductor components. These components are able to change the resistance without metal. They differ from RTDs by:
- Having narrowest measuring range
- Having the highest sensitivity
- Having low linearity and stability
The ideal time to use a thermistor is when applications are not too critical. Ideally, the devices will be measuring temperatures lower than 1000 degrees Fahrenheit. This is because of the fact that thermistors are made from ceramics or polymers, where as RTDs are made from pure metals. A thermistor also works between limited temperature rangers, as opposed to RTDs that have a wider spectrum.
Thermistors
Getting a full grasp of different measuring options is no easy task, and so the journey should not be undertaken alone. When acquiring Thermistors, RTDs, or Thermocouples, you should contact a professional in the industry who can help you choose the best possible device.