For any task requiring the measurement of pressure, choosing the most suitable measuring technique is of the upmost importance. First Sensor is a leading manufacturer of platform-based pressure sensors and aims to provide sensor solutions for any application-specific requirement. In this article, the difference between absolute, relative and differential pressure sensors is explained and specific application examples are provided.
Absolute pressure sensors monitor pressure relative to a vacuum within the sensor element. Application examples requiring the use of absolute pressure sensors include measurement of meteorological air pressure and vacuum packaging of food.
Relative pressure sensors monitor pressure relative to the ambient air pressure, which reaches the sensor through a small ventilation hole. The pressure measurements produced by the sensor are either lower than the ambient pressure, termed ‘negative pressure’, or greater than the ambient pressure, termed ‘overpressure’. As such, pressure changes within the external environment affect the value obtained by the sensor. Applications that may benefit from the use of relative pressure sensors include measurement of tire pressure, hydrostatic level measurement in ventilated tanks or open containers, and medical suction devices that create a negative pressure.
Although differential pressure sensors bear some similarities to sensors for relative pressure, one major difference can be used as a distinction; they can measure pressure not only in relation to ambient air pressure, but also in relation to any other pressure. This is because differential pressure sensors utilize a second pressure connection, typically hose, manifold or threaded – relative pressure sensors only have one pressure connection. Application examples include respiratory flow measurement in medical technology, volume flow measurement in air conditioning and filter monitoring.
This information has been sourced, reviewed and adapted from materials provided by First Sensor AG.
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