Sensors for Humidity Measurement

Capacitive Relative Humidity Sensors

IST provides exclusive humidity sensors with directly integrated platinum temperature sensors that cater to a wide range of applications.

IST's humidity sensor product line features sensors with excellent linearity, low hysteresis, fast response times, and high chemical resistance. Our thin-film capacitive relative humidity sensors are capable of measuring 0 to 100% relative humidity and operating at temperature ranges of -80°C to +190°C. 

Some of the key features include:

  • Humidity range: 0 % RH to 100 % RH
  • Temperature range: -80 °C to +190 °C
  • Dimensions: Various dimensions (details see data sheets)
    • Length between 4 and 10.8 mm
    • Width between 2 and 3.8 mm
  • Connection: With various lead wires (several materials, wire length can be adapted individually) or as SMD

Further features:

  • Excellent linearity
  • Low hysteresis
  • Fast response time
  • High chemical resistance
  • Resistance to condensation
  • Very low drift

    Customer-specific adaption possible

Measurement Principle

Capacitive RH sensors consist of a ceramic substrate on which a thin-film of polymer is deposited between two conductive electrodes. The sensing surface is coated with a microporous metal electrode, allowing the polymer to absorb moisture while protecting it from contamination and exposure to condensation. As the polymer absorbs water, the dielectric constant changes incrementally and is nearly directly proportional to the relative humidity of the surrounding environment. Thus, by monitoring the change in capacitance, relative humidity can be derived.

Sensor Configurations

  • Wired
  • SMD
  • Modules

Our Technology

The core technology of all IST products is thin-film deposition, in which a thin layer of metal is deposited onto a ceramic substrate. This technology allows for the production of extremely small sensors with enhanced operational capabilities such as:

  • Improved response times
  • Robustness
  • Packaging versatility 

Our thin-film technology is second to none for applications requiring long-term stability and accuracy in wide temperature ranges. Using our expertise in thin-film deposition, we develop measurement solutions that are consistent and reliable.

IST AG has one of the best equipped front-end production lines for thin-film sensors, operating in clean rooms to class 1000. The fully automatic assembly technology ensures the highest quality product with an optimal price-performance ratio. Precise measuring instruments in our laboratories allow for the calibration of our products in the areas of temperature, humidity and flow.


IST humidity sensors are used in a wide variety of industries, including:

  • Building Automation
    The Heating Ventilation and Air-condition (HVAC) market in the Building Automation industry focuses on controlling atmospheric conditions to make them more suitable. IST’s thin-film capacitive humidity sensors are ideal for controlling the relative humidity of an environment due to their rapid response times and accuracy over time. 
  • Appliances
    IST's capacitive RH sensors are ideal for the long term precise measurements required by the consumer appliance industry. Applications includes Dewer Humidity Control Modules.
  • Medical
    IST's precise and reliable sensors meet the needs of the medical industry, which requires the accurate and consistent performance of its equipment. Humidity sensors also have an application in the medical industry in products that control the air present or supplied to the patient. Applications include respirators and incubators.
  • Test & Measurement
    Test and measurement is an industry in which highly accurate and stable sensors are crucial. Our sensors can be directly integrated into instruments. Applications include humidity data loggers, dew point handheld devices, weather balloons/stations, and humidity chambers.
  • Process Control
    IST's diverse family of sensors meet the needs of this industry for measurement and control, which determine the effectiveness of products. Applications include greenhouse modules and discharge air monitoring.
  • Automotive
    New innovations in the automotive industry have created a need for accurate and robust measurement methods. IST’s humidity sensors are used in several automotive applications, including windshield fogging and in-cabin comfort.

IST USA Division offers a high degree of flexibility in sourcing and supporting our products. We offer in-house stock and on-site engineering support, which is available during our regular business hours for design, application, and after sales support.

Our Sensor Offerings Include:
Temperature | Humidity | Flow | Conductivity | BioSensors | Thin-Film

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