Frequently Asked Questions (FAQ)

Question: What is an absolute pressure sensor?

Answer: Absolute pressure sensors measure the applied pressure in comparison to the absolute vacuum.

Question: What is a relative pressure sensor?

Answer: Relative pressure sensors measure the difference between the ambient pressure and the measuring pressure.

Question: What is a barometric pressure sensor?

Answer: Barometric pressure sensors measure the air-pressure comparative to the vacuum.

Question: How can you measure the altitude with the help of an absolute pressure sensor?

Answer: The geographic altitude and the atmospheric pressure are interconnected via the classic barometric formula. By using an absolute pressure sensor the atmospheric pressure can be detected easily. You will find more information about this topic in the application note aan509.

Question: What is a differential sensor?

Answer: Differential pressure sensors measure the difference between two measuring pressures. For more detailed information please read the application note: aan505.pdf.

Question: What is a bidirectional difference sensor?

Answer: Bidirectional Difference Pressure Sensors measure the difference between two measuring pressures, in doing so it doesn’t matter which pressure is higher or lower. In this way low and high-pressure can be measured comparative to a given pressure.
Link: aan505.pdf.

Question: What is a ratiometric sensor?

Answer: A ratiometric sensor is a sensor whose output signal changes synchronously with the changing of the supply voltage.

Question: How do you protect silicon sensors against liquids?

Answer: Pressure sensors with silicon measuring cells are sensitive to liquids and a multitude of aggressive substances. The article describes which arrangements can be made to reduce the feared media sensitivity of relative- respectively difference pressure sensors dramatically.
Link: Article aan508

Question: How do you calibrate ceramic measuring cells?

Answer: This article describes in detail a simple electronic circuit based on a suitable IC and few external components to amplify and to calibrate the offset- and full span-signal of ceramic sensing elements. The aim is to create a ready-to-mount sensor system with a ratiometric output signal and a suitable level of precision without a temperature compensation.
Link: Article aan504.pdf

Question: What is a pressure sensor module?

Answer: Pressure sensor modules are pressure sensors, whose output signals have to be calculated by an external microprocessor.

More answers on technical questions concerning the sensors of Intersema and MEAS can be found here: MEAS Inc.