Resistance temperature detectors

Part of our core range of temperature sensors, resistance temperature detectors (RTD) are an industrial sensor used to measure temperatures. Suitable for use across a range of critical applications, we supply RTDs to professionals in industries ranging from vehicle manufacturing to commercial food handling and processing.

Resistance temperature detectors consist of fine wires wound into a coil around a non-conducting ceramic or glass core. These wires are made of platinum – although nickel and copper are also used – and are encased in a ceramic or glass probe to protect them. The number of wires in RTD devices varies, so you can filter your search to find the correct component – whether you're looking for a 2-wire or a 4-wire RTD.

We stock RTD models from many of the biggest industry brands. Whether from Honeywell, RS Pro or SICK, you can rest assured that you'll receive quality components from suppliers we know and trust. Browse our selection to begin your order today, and please don't hesitate to contact us if you need any advice.

How do resistance temperature detectors work?

All resistive temperature sensors are passive, which means they don't produce an output independently. Instead, external devices pass a small electrical current through the RTD to measure its resistance.

Each RTD contains one resistance element alongside its insulated platinum wires. The resistance of an RTD changes in response to temperature fluctuations: as the temperature of the metal increases, so does the resistance to the flow of electricity. For every increase in temperature, per degree, the resistance changes according to the temperature coefficient.

This coefficient is a set ratio: for platinum RTDs with a base resistance of 100 Ohms at 0°C, the temperature coefficient is .00385. As electrical current passes through the sensor, temperature can therefore be measured by the total resistance reading.

Why is platinum used in temperature sensors?

Platinum is the most suitable metal for use in RTD temperature sensors, largely due to its ability to provide reliable, measurable results across a broad temperature range. Additionally, platinum's stability means that it rarely provides anomalous readings, enabling increased precision in temperature measurement.

Which resistance temperature detector types are available?

Where resistance is concerned, most of the resistance temperature detectors in our online selection are Pt100, meaning they have a base resistance of 100 Ohms at 0°C. However, if you require an RTD with a higher resistance, we also have Pt500 and Pt1000 resistance temperature sensors in our selection.

When it comes to the RTD body style, we have several types available, including:

Cylindrical

Resistance temperature detectors in a cylindrical style make a popular choice for use within tubes, pipes, or protective sheaths. Such geometry also offers accurate readings in confined environments, complemented by a flexible probe. The RS PRO 3706587 is a platinum RTD with a 5mm probe, suitable for measuring temperatures ranging from -20°C to 100°C.

Thin film

Our thin film resistance temperature detectors are manufactured by placing a thin layer of resistive platinum onto a ceramic core. A specific pattern is then etched onto the outer element, forming an electrical circuit. Thin film RTDs provide a reliable, almost linear relationship between temperature and resistance, along with a higher accuracy across a broad range of temperatures.

Heavy duty

We also have an excellent selection of heavy duty RTDs available. We stock RTDs suitable for use in even the most hazardous, high-risk applications, with explosion-proof models including the Dwyer Instruments TTE-104-W-LCD featured in our collection. This model also includes a useful LCD screen, allowing the user to configure it to any range between -30°F and 250°F.

What is a resistance temperature sensor used for?

RTDs are commonly used in food production thanks to their ability to provide accurate readings over smaller temperature ranges, along with their long-term stability. A few of the applications of resistance temperature detectors include:

• Automotive industry: to monitor engine temperature, oil level sensors, and air intake temperature sensors
• Electrical equipment: tracking temperature of amplifiers, stabilisers for transistors, etc.
• Cooking equipment: probes in ovens, toasters, and grills
• Food processing: in brewing, refrigeration, pasteurisation, and bottling
• Plastics processing: in extruders, injection-moulding machines, thermoforming machinery, etc.

Order your RTD from RS

We have a wide variety of resistance temperature detectors from which to choose, ensuring that you can take care of your needs for precise, reliable temperature measurement. As one of North America's largest suppliers of high-quality components, you can always rely on us to deliver exceptional performance, no matter your requirements or budget.

We aim to provide a level of customer support that matches our superior product offering. If you have any questions regarding our RTD products or the service we offer, don't hesitate to get in touch with us today. You can also head over to our expert hub to find a selection of exclusive resources and industry know-how.

Regardless of your desired application for a platinum resistance temperature detector, we will deliver the part you need – and quickly.