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Digital capacitive humidity sensor

Capacitive relative humidity sensors from Sensirion have become the market standard, since they were launched in 2002. Thanks to its CMOSens® technology, they allow precise humidity and temperature measurement at low cost. Humidity sensors from Sensirion are used widely in diverse applications such as climate control, building control, the automotive industry, data loggers, transmitters, consumer goods, and many more.

The SHT11 digital humidity sensor and temperature sensor is fully calibrated and offers excellent long term stability and ease of use at very low cost. The digital CMOSens® Technology integrates two sensors (humidity sensor and temperature sensor) and readout circuitry on one single chip.

Product features
* 2 sensors for relative humidity & temperature
* Precise dewpoint calculation possible
* Humidity sensor measurement range: 0-100% RH
* Absolute RH accuracy: +/- 3% RH
* Temp. accuracy: +/- 0.4°C @ 25 °C
* Calibrated & digital output (2-wire interface)
* Fast response time < 4 sec.
* Low power consumption (typ. 30 µW)
* Low cost
* Designed for high-volume applications
* Leading CMOSens® Technology for superior long-term stability
* Very easy-to-use due to calibration & digital 2-wire interface

For humidity sensors with CMOSens® technology, a "micro-machined" finger electrode system with different protective and polymer cover layers forms the capacitance for the sensor chip, and, in addition to providing the sensor property, simultaneously protects the sensor from interference in ways previously not achieved.

Humidity, temperature and dewpoint
The temperature sensor and the humidity sensor together form a single unit. This also enables an accurate and point-precise determination of the dew point, without incurring errors due to temperature gradients between the humidity and the temperature sensors. Through the unique linkage of these sensor elements with the signal amplifier unit, the analog-to-digital converter, the calibration data memory, as well as the digital, bus-ready interface, all on a surface area of a few square millimeters.

Highest stability and performance
Total coverage with condensation or even immersion in liquid present no problems whatsoever. Over two years of hardness tests have already shown this result.
The signal amplification near the sensor allows the polymer layers to be optimized not for the signal strengths, but rather for long-term stability, which is significant for numerous applications. The analog-to-digital conversion, which is also performed "in place," makes the signal extremely insensitive to noise. A checksum generated by the chip itself is used for additional reliability. Last but not least, the calibration data loaded on the sensor chip guarantees that Sensirion humidity sensors have identical specifications and thus they can be replaced 100%. Other obvious advantages are the very short response times (4 sec at 1/e), high precision (±2% to ±5% according to configuration), as well as very low power consumption (< 3mA standby).

Digital interface
Humidity and temperature sensors with CMOSens® technology can be connected directly to any microprocessor system by means of the digital 2-wire interface, which minimizes the system development times, saves costs, and leads to a significant advantage, especially for high-volume applications.

Manufacturer/supplier's information

Company name:		Sensirion - the sensor company [ Homepage ]
Business address:		Sensirion AG Laubisruetistrasse 50 CH-8712 Staefa ZH Switzerland
Telephone number:		+41 44 306 40 00
Contact name:		Tobias Loher [ Email ]

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Product groups: sensor   humidity sensor   capacitive humidity sensor   moisture sensor

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Other products at Sensors, transducers, detectors > Humidity sensor

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