top of page
  • Writer's picturePerceptive Things Team

Types of Temperature Sensors



Temperature measurement plays a big role in many industries and processes, which makes temperature sensors a valuable tool for ensuring accuracy.


If you are a building owner who is interested in learning more about temperature sensors, then this post is the perfect guide to unraveling the mysteries of this technology.


We will provide an overview of how temperature sensors work and explore some of their uses. We will also provide insight into why they are important and how they can help your building stay protected.


The 4 Types of Temperature sensors


Temperature sensors are used to measure and monitor the temperature. The most common use for a temperature sensor is in a thermostat. When the temperature sensor is triggered, it tells the thermostat to regulate the temperature of a room or building.


Beyond commercial and residential uses, temperature sensors can also be used in industrial and automotive applications. They are popular for monitoring the temperature of engines, fluids, and other machinery.


Temperature sensors come in many different shapes and sizes. They also use different methods to measure temperature.


The 4 types of temperature sensors are:

  1. Thermocouples

  2. Resistance Temperature Detectors (RTD)

  3. Thermistors

  4. Semiconductor-based integrated circuits

Thermocouples


The most commonly used type of temperature sensor is thermocouples. You may even have a few thermocouples in your home because they have various applications, from industrial to consumer.


One of the best things about thermocouples is that they are affordable and can operate in a wide temperature range without needing excitation. These temperature sensors are self-powered and have quick response times, making them very convenient.


Thermocouples represent a device with two joint dissimilar metal wires; when the wires touch, they produce a temperature-dependent voltage, also known as the Seebeck Effect. You can use this voltage to measure and calculate the temperature.


There are various types of thermocouples made of different materials with unique sensitivities and temperature ranges.


Here’s a chart showing multiple types of thermocouples.


Thermocouple Types and Characteristics (revised from Digi-Key's adaptation of “Tutorial 6500 Temperature Sensor Tutorial”)

The K type and N type have the most widespread usage, although you can use other types as well, depending on your needs.


Although there are a lot of benefits to thermocouples, they also have a couple of drawbacks. One of their biggest disadvantages is that they have a small output voltage, which can make it hard to measure the temperature.


Pros:

  • Various usages

  • Durable

  • Various available types

  • Affordable

  • Operate in a wide range of temperatures

  • No need for excitation

  • Easy to read

Cons:

  • Small output voltage

  • Occasionally hard to use to measure the temperature

  • Low sensibility

Resistance Temperature Detectors (RTD)

Another common type of temperature sensor are resistance temperature detectors, known as RTDs. These temperature sensors are highly accurate, which is why they’re slowly replacing thermocouples in various applications.


RTD elements consist of a fine wire wrapped around a core which is typically heat-resistant or glass. The wire material has a good temperature-resistance relationship; with temperature changes, the resistance of the material changes as well.


The wire that resistance temperature detectors use is a pure material, with the most common RTD materials being:

  • Platinum

  • Nickel

  • Copper

Although RTDs can have wires out of various materials, platinum is the most commonly used material to make RTDs because it has the highest accuracy.


These RTDs, commonly known as PRTDs, are stable, accurate, and have a wide temperature range. They also provide repeatable responses and offer almost a linear response to any temperature changes. Because of these benefits, people use RTDs in applications where high precision is necessary.


RTDs come in different configurations, with options with two, three, and four wire RTDs. Here’s what you should know about them:

  • Two-wired RTD — The best option is if the lead length is short so that the measurement accuracy won’t be affected by the resistance. This is also the simplest RTD circuit design.

  • Three-wired RTD — This RTD has a probe that carries the excitation current, canceling the wire resistance.

  • Four-wired RTD — The most accurate type of RTDs, because wire resistance is eliminated by a separate force and sense leads.


While there are excellent features that set RTDs apart from other temperature sensors, there are also many drawbacks to RTDs. One of the biggest disadvantages of resistance temperature detectors is that they have a slow response time due to their high thermal mass.


Pros:

  • Very accurate

  • Precise

  • High accuracy

  • Linear

  • Predictable

  • Stable output

  • Easy to install

Cons:

  • Expensive

  • Low sensitivity

  • Slow response time

  • Self-heating

Thermistors


Another type of temperature sensor is the thermistor, which is made from a material that changes resistance with temperature, typically ceramic or polymer. Thermistors are usually used in circuits that require a precise reading, and they are similar to RTDs.


These temperature sensors are commonly affordable, have good sensitivity, and come in two-wire configurations. However, they’re not as accurate and precise as RTDs are, which is something to keep in mind when choosing between the two.


The two main types of thermistors are Negative Temperature Coefficient (NTC) thermistors and Positive Temperature Coefficient (PTC) thermistors.


Here are they key details of these two types of thermistor:

  • NTC thermistors This is one of the most commonly used types of thermistors in temperature measurement applications. As the temperature in a room increases, the resistance of this thermistor decreases.

  • PTC thermistorsThese thermistors are less used, although they’re also available. As the temperature in a room increase, the resistance of this thermistor increases as well.

Since these devices have a non-linear relationship with temperature resistance, the data can expand the measurements you get. That said, such a measurement will probably need correction in order to show the proper data.


Pros:

  • Good sensitivity

  • Fast response

  • Affordable

  • Small size

Cons:

  • Not as precise and accurate as RTDs

  • Non-linear

  • The data can expand the measurement

  • Data might need corrections

  • Fragile

  • Self-heating

Semiconductor-based integrated circuits


These temperature sensors function with dual integrated circuits, which is why they got the name semiconductor-based integrated circuits.


There are two main types of semiconductor-based integrated circuits:

  • Local temperature sensor

  • Remote digital temperature sensor

Local Temperature Sensor


These sensors represent integrated circuits that use the physical properties of transistors to measure their own die temperature. They sense the temperature directly on the printed circuit boards or from the ambient air around the printed circuit boards.


Depending on your needs, you can use local temperature sensors on both analog and digital outputs, although their voltage will vary. Analog outputs can typically have any voltage or current, while digital outputs have several formats.


Remote Digital Temperature Sensor


Remote digital temperature sensors represent integrated circuits that measure the temperature of external transistors. When it comes to their function, they work based on the same principle as local temperature sensors by using a transistor’s physical properties.


However, there’s one significant difference between them.


The difference between local and remote digital temperature sensors is that in remote digital temperature sensors, the sensor chip and the transistor are located away from one another.


Pros:

  • Low power consumption

  • High output

  • Affordable

Cons:

  • A power supply is required

  • Slow in operation

  • Limited configurations

  • Self-heating

Which Type of Temperature Sensor is the Best?


Determining which type of temperature sensor is the best can be quite difficult because each type has its own pros and cons. You also need to consider the application and industry for which you need the temperature sensor.


If you need a sensor that’s highly accurate, RTD should be your choice. However, thermocouples, semiconductor-based integrated sensors, and thermistors are also wildly used. Remember to compare all the types that would work for you and choose the one that suits you the most.


Popular Temperature Sensors for Commercial and Multi-family Buildings


If you are looking for a temperature sensor for your building, Perceptive Things® has a suite of sensors available to help you gain insights like never before.


Our sensors can be used to monitor and track readings over time. They will keep tabs on your building 24/7, so you can know your building is in good hands even when your staff is off duty or away from your location.


Our two temperature sensors are Mercury™ and Mercury Surface™. Keep reading to learn more about what makes these sensors unique!


Mercury™


Our ambient temperature and humidity sensor can be mounted anywhere. Our platform enables instant notifications when the temperature or humidity rises above or falls below a configurable threshold. No matter where it is placed, Mercury™ can help you ensure a consistent and safe environment.


Mercury Surface™


Our surface mounted temperature sensor can gives you instant notifications when when the temperature or humidity rises above or falls below a configurable threshold.


Mercury Surface™ will alert you of overheating or cool-down conditions within minutes via call, text, and email. You can trust Mercury Surface™ to protect your assets and ensure smooth operations.


You can use Mercury Surface™ to monitor:

  • pipe temperatures

  • electric motors

  • electrical equipment & more!

If you are interested in learning more about Mercury™ or Mercury Surface™, please email us at contact@perceptivethings.com. We look forward to hearing from you!

20 views0 comments
Post: Blog2_Post
bottom of page