RTD Pt100 Sensors

What is a Pt100 Sensor and how do they work?

An RTD Pt100 is a type of temperature sensor which relies on the priniciple that as a conductor heats or cools, it's resistance changes in response to the temperature change and so provides a measurable resistance which can be used to give an accurate measurement of the temperature. 'RTD' is an acronym of Resistance Temperature Detector.

The choice of the conductor in the case of a Pt100 is platinum (Pt), which is chosen because of its relatively high resistivity and wide temperature range as well as for being stable, to provide a resistance of 100 ohms @ 0ºC (hence Pt100). This is usually achieved by a coil of platinum suspended in a ceramic former or by platinum deposited on a film substrate to provide a sensing element. A Pt100 has a change in resistance between 0ºC and 100ºC of 38.5ohms. This value is known as the fundamental interval. For more information on the relationship between temperature and resistance for Pt100 sensors, please click here.

This Pt100 element is then inserted in to a stainless steel protection tube with wires attached to it to make the resistance thermometer (sometimes known as an RTD Sensor). The sensor wires are then usually attached to a connector, extension cable or terminal head ready to connect to instrumentation.

For a more detailed technical explanation on RTD Pt100 resistance thermometer theory, why not request our free guide to resistance thermometry which includes an illustrated 37,000 word explanation on the theory of temperature measurement?

Choose the right Pt100 RTD Sensor for your application

We have a wide range of Pt100 RTD Sensors designed to meet the requirements of most temperature measurement applications available from stock for Next Day Delivery!

What is the difference between 2-wire, 3-wire and 4-wire RTD Pt100 Sensors?

As mentioned above, resistance thermometers utilise a change in the resistance of a conductor to provide a measurable indication of temperature. A sensing element is manufactured which gives a resistance of 100 ohms @ 0ºC and any change in resistance due to temperature change is then measured and converted to ºC or ºF by the instrumentation. However, the sensing element must be connected to the instrument to measure this resistance and this will involve attaching extension wires to the element. These wires will have an inherent resistance which must be accounted for in the measurement to avoid errors being introduced as a result of lead resistance. 3-wire and 4-wire resistance thermometers accomplish this, please click here for more details.

RTD Pt100 sensors for industrial temperature measurement applications come in a wide range of constructions, each designed for a particular set of parameters. From budget RTDs to Precision Pt100 sensors, we have RTD sensors for most applications available from stock.

RTD sensors are available with a choice of terminations such as; with extension cable, miniature connectors, Lemo connectors and terminal heads. We also have sensors available with 4 to 20mA transmitters fitted for process applications.

We supply air temperature sensors and a range of Pt100s for surface temperature measurements as well as specialist sensors designed for use in autoclaves, plastics machinery as well as a range of miniature RTD sensors for applications where both accuracy and a fast response to changes in temperature is required.

What are wiring details and colour codes for Pt100 Sensors?

Pt100 sensors are colour coded according to whether they are 2, 3 or 4-wire devices.

What are the specifications for Pt100 Sensors?

Pt100 sensors have different tolerances, standards and temperature ranges.

Do I need a Pt100 RTD or Thermocouple?

There are many factors to consider when choosing the correct temperature sensor for your application. The main criteria will be the temperature range, accuracy and response time.

What cable do I use for Pt100 sensors?

RTD Pt100 sensors do not require dedicated materials as thermocouples do, but we have a wide range of cables for use with Pt100 sensors in various insulation materials.