Accurate and reliable recording of humidity and temperature is crucial to the safe operation of electrical systems and equipment. Sensirion have established themselves as one of the world's leading manufacturers of heat and humidity sensors, setting global standards for performance, reliability and miniaturized form factor.
The SHT1 and SHT7 range of humidity and temperature sensors are based on CMOSens® Technology, which combines the strengths of standard CMOS production processes and advanced MEMS technology and packages them into the tiny footprint of a single silicon chip. Surface mount and plug-in versions of the sensor are now available from Rapid Electronics. Humidity is sensed using a capacitor, and the dielectric is realised through a polymer, which absorbs or desorbs water depending on the ambient humidity.
The change in capacitance can be measured by an electronic circuit, therefore determining the relative air humidity. The temperature sensor and humidity sensor together form a single unit, enabling accurate and point-precise determination of the dew point, without incurring errors due to temperature gradients between the humidity and temperature sensors.
Both sensors are seamlessly coupled to a 14bit analog to digital converter and serial interface circuit. This produces significant gains in signal quality, fast response time and insensitivity to EMC.
The sensors can be fully immersed in liquid without any deterioration in performance. The SHT71 and SHT75 are plug-in digital pin-type devices, while the SHT11 and SHT15 are surface mounted reflow solderable sensors. Long term stability and low energy consumption makes the components ideal for remote applications.
Technical specifications
Output: digital (2-wire interface)
Supply voltage range: 2.4 to 5.5V
Energy consumption: 80µW (at 12bit, 3V, 1 measurements/ s)
Relative humidity operating range: 0-100% RH
T operating range: -40 to +125°C (-40 to +257°F)
RH response time: 8 sec (tau63%)
Filter caps and evaluation kits are also available. For more information visit the Rapid Electronics website - www.rapidonline.com – or call Rapid on +44 (0)1206 751166.
