{"id":8212,"date":"2023-09-13T09:00:17","date_gmt":"2023-09-13T14:00:17","guid":{"rendered":"http:\/\/blog.wika.com\/us\/\/?p=1397"},"modified":"2025-02-03T15:31:59","modified_gmt":"2025-02-03T20:31:59","slug":"rtd-vs-thermocouple-when-to-use-each-product","status":"publish","type":"post","link":"https:\/\/blog.wika.com\/us\/products\/temperature-products\/rtd-vs-thermocouple-when-to-use-each-product\/","title":{"rendered":"RTD vs. Thermocouple: When To Use Each Product"},"content":{"rendered":"

Temperature sensors are essential measuring instruments for ensuring the safety and efficiency of countless industrial processes. While RTDs and thermocouples both provide accuracy and reliability, each has pros and cons that make them better suited for particular applications.<\/strong><\/p>\n

Resistance thermometers (RTDs)<\/a> and thermocouples<\/a> are the two most common types of electronic temperature sensors<\/a>\u00a0used in industrial processes. The choice of which one to use depends on a variety of factors. First let\u2019s take a look at what RTDs and thermocouples are, and how they differ from one another.<\/p>\n\n

RTD<\/p><\/div>\n \n

What is an RTD, and how does it work?<\/a><\/h2>\n

RTD stands for resistance temperature detector. This instrument is also called a resistance thermometer and, redundantly, an RTD probe or RTD sensor.<\/p>\n

Within an RTD is a sensing element (resistor) that uses the change in electrical resistance of metal to determine the temperature. The most common metal in RTDs is platinum (Pt), as it is very chemically inert and has an almost linear temperature vs. resistance relationship. Platinum RTDs are often referred to as Pt100 sensors or Pt1000 sensors<\/a>; the number refers to platinum\u2019s nominal resistance (ohm \u03a9) at 0\u00b0C. Other metals used in RTDs are copper, nickel, and tungsten, but WIKA\u2019s RTDs are made of platinum primarily because this metal has excellent stability, resists contamination, and its electrical resistance does not degrade over time.<\/p>\n

Regardless of the metal used, its electrical resistance at specific temperatures is a known constant. As the temperature changes, so does the metal wire\u2019s resistance. So, by comparing the known resistance to the measured resistance, one can calculate the temperature.<\/p>\n

Types of RTDs<\/h2>\n\n

Thin-film (left) and wire-wound resistors<\/p><\/div>\n \n