From RS Pro a high-quality and reliable Pt100 PRT (Platinum Resistance Thermometer) or RTD (Resistance Temperature Detector). This Pt100 RTD has a sensing element that is encased in silicone rubber patch so it can be used to measure the temperatures on surfaces. The twisted leads are 4 core with a durable and flexible Teflon insulation. This platinum resistance thermometer provides accurate and reliable temperature measurement for a wide range of applications.

An RTD is a type of temperature sensor based on the correlation between metals and temperature. As the temperature of a metal increases so does its resistance to the flow of electricity. This resistance can be measured and converted to a temperature reading. In a Pt100 RTD, the ’Pt’ stands for platinum (platinum wire or film) and ’100’ means that the temperature sensor has a resistance of 100 Ohms at 0°C. Platinum is the most reliable metal due to its linear resistance to temperature relationship over a large temperature range.

A Pt100 silicone patch sensor is designed to measure the temperature on surfaces. The temperature sensor element is embedded inside a silicone patch. One side of this patch has a self-adhesive aluminium foil backing allowing the sensor to be stuck firmly in place. The other end of the sensor is terminated by 4 wire tails which are connected to the temperature measuring equipment.

• High stability sensing element with a precision output
• IEC 60751 Class B accuracy/tolerance
• Self-adhesive silicone patch for mounting onto a surface
• Silicone patch offers durability and resistance to many oils and chemicals
• Teflon insulated leads for thermal and electrical insulation, impact strength and protection against moisture, corrosion and abrasive chemicals even in extreme temperatures
• Temperature measurement range of -50 to +150°C
• 4 lead wires for accurate readings

These Pt100 PRT silicone patch sensors with their compact and versatile design are most commonly used in pipe or surface measurement.

The PRT temperature sensor works by placing the sensor element (or process end) into the equipment or process that requires temperature measurement. As the temperature of the platinum resistance thermometer increases it’s resistance to the flow of electricity increases. For every increase per degree of temperature the electrical resistance also changes by a set ratio, this is called the temperature coefficient. For platinum, this ratio is .00385 ohm/ohm/°C which means for a Pt100 with a 100 ohm resistance the increase in resistance per degree of temperature would be 0.385 ohms. The total resistance reading can, therefore, be measured and converted into temperature.

The resistance generated by the temperature sensor is measured by passing current through one of the wires to produce a voltage. This voltage is then measured using a suitable bridge or voltmeter and the resistance calculated in ohms using Ohm’s Law (R=V/I). Once the resistance is known you can convert it to a temperature reading using a calibration equation or a Pt100 table. A temperature measurement device or calibrator can also be connected to the leads of the probe that will automatically convert the measured resistance into a temperature reading