Vaisala HUMICAP® Sensor for Measuring Relative Humidity

Vaisala Humicap sensor structure
Science & Sensing Technologies
Industrial Measurements
Life Science

Until the early 1970s, hair hygrometers were commonly used in radiosondes. At that time, reliable humidity measurement was an unresolved challenge and to solve this, Vaisala began developing a new type of humidity sensor using semiconductors and thin-film materials. The revolutionary HUMICAP humidity sensor was introduced two years later, in 1973, at CIMO VI congress. HUMICAP was a radical innovation that changed humidity measurements for good. The new technology was groundbreaking: the sensor had no moving parts, and due to the advanced use of semiconductor and thin-film technologies, it was amazingly small. The sensor had a fast response time, good linearity, low hysteresis, and small temperature coefficiency.

Despite the fact that the innovation was designed for a new type of a radiosonde, the greatest interest came from elsewhere: people working in environments as diverse as greenhouses, bakeries, warehouses, construction sites, brick and timber kilns, and museums. The need for reliable humidity measurement was common to all, and instruments that could do this accurately were few and far between. By 1980, a variety of products based on HUMICAP technology – from hand-held meters to industrial transmitters, calibrators, and other accessories – were being sold in over 60 countries. Since its birth, HUMICAP has been part of Vaisala’s core business, propelling the company to industry leadership in the field of humidity measurement.

HUMICAP’s Unique Benefits

Excellent long-term stability

Insensitive to dust and most chemicals

Chemical purge option for stable measurements in environments with high concentrations of chemicals

Sensor heating for measurements even in condensing environments
Full recovery from condensation