Issue link: https://resources.mouser.com/i/1437663
mouser.com/amphenol 13 Temperature measurement for reliability Thermistors are critical for temperature measurement in HVACR and IAQ systems. These electrical devices vary their electrical resistance with temperature following a logarithmic curve. Measuring each device's resistance determines the ambient temperature of the sensor. Glass encapsulated thermistors are more stable than RTDs. Thermistors, whether glass or epoxy coated, will maintain ±0.2°C across large temperature intervals. NTC thermistors should meet the IP68 waterproof standard rating, which enables withstanding dust, dirt, and sand and having resistance to submersion up to a maximum depth of 1.5m under water for up to 30 minutes. NTC Thermistors are for ventilation, refrigeration, under-floor heating, water heaters, and heat pumps. NTC thermistor sensors can be hermetically sealed in glass for high temperatures such as 150°C. They are available in surface mount, harsh environment, miniature, radial lead, glass encapsulated beads, and more. Performance monitoring in oil These sensors have oil-proof versions and are compatible with engine and gear oils used in the automotive industry and in most liquid and gas media. They are small and lightweight with an aluminum housing option. High-precision versions are available. Applications include measurement and testing technology, oil pressure applications in motor and commercial vehicles, braking systems, and powertrains. Output signal options offer 4mA to 20mA, two-wire systems, 0V to 5V, 1V to 6V, 0V to 10V, and 0.5V to 4.5V ratio metric. Housings are usually stainless steel, aluminum with a stainless-steel silicon measurement sensing element (also with a stainless-steel membrane and oil-filled). Temperature range is typically -40°C to +125°C. Gas Sensors for R32 and R290 Refrigerants Refrigerant gas sensors might have a microcontroller and software to enhance reliability while minimizing the probability of faults. Designers incorporate infrared sensors into their gas detection instrument to significantly reduce the development time and expertise required during the design and implementation phases. This means fast time to market. Figure 3: This image shows the equivalent circuits for analog-only, I2C, or SPI interfaces. (Source: Amphenol) "Thermistors are critical for temperature measurement in HVACR and IAQ systems."