Pressure Measurement · Glossary

What is a Capacitive Pressure Sensor?

diaphragm between capacitor platesPressure Measurement

A capacitive pressure sensor measures pressure from the change in capacitance as a diaphragm moves between fixed plates.

Capacitive Pressure Sensor Explained

In many DP transmitters a central sensing diaphragm sits between two fixed plates. Pressure moves it towards one plate, raising one capacitance and lowering the other; the difference gives DP.

Capacitive sensors offer good stability and overpressure tolerance, and work well for low ranges.

Capacitive Pressure Sensor Formula

C = ε × A ÷ d

ε	permittivity of the dielectric
A	plate area
d	gap between plates

Calculators for Capacitive Pressure Sensor

CalculatorTransmitter Turndown CalculatorFree online calculator with formula and worked example.

Frequently Asked Questions

What is a Capacitive Pressure Sensor?

A capacitive pressure sensor measures pressure from the change in capacitance as a diaphragm moves between fixed plates.

Why use two capacitors?

A differential arrangement doubles sensitivity and cancels many common errors such as temperature effects on the fill.

Are capacitive sensors good for DP?

Yes. Many DP transmitters use them because they handle low ranges and high static pressure well.

Learn more on the blog

Differential pressure transmitter working principle

A practical guide on instrumentationblog.in with more detail on capacitive pressure sensor and how it is applied on real plants.

Read Full Article

More Pressure Measurement Terms

Pressure termManometerA manometer measures pressure from the height difference of a liquid column in a U tube or inclined tube.Pressure termWater HammerWater hammer is the pressure surge created when a moving liquid is suddenly stopped, for example by fast…Pressure termPressure SnubberA pressure snubber is a restriction fitted before a gauge or switch to damp pulsation and pressure spikes.Pressure termPressure Gauge SiphonA pressure gauge siphon is a looped or U shaped tube fitted below a pressure gauge on steam to keep hot…Pressure termPressure Switch DeadbandPressure switch deadband is the difference between the pressure at which a switch trips and the pressure…Pressure termPressurePressure is force acting per unit area. In fluids it acts equally in all directions at a point.

All pressure measurement terms · Full glossary A to Z