A pressure sensor measures pressure, typically of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area.
Published on: Mar 4, 2016
Transcripts - Pressure sensor
Pressure sensor | Isweek.com – Industry sourcing
A pressure sensor measures pressure, typically of gases or liquids. Pressure is an
expression of the force required to stop a fluid from expanding, and is usually stated in
terms of force per unit area. A pressure sensor usually acts as a transducer; it generates
a signal as a function of the pressure imposed. For the purposes of this article, such a
signal is electrical.
Pressure sensors are used for control and monitoring in thousands of everyday
applications. Pressure sensors can also be used to indirectly measure other variables
such as fluid/gas flow, speed, water level, and altitude. Pressure sensors can
alternatively be called pressure transducers, pressure transmitters, pressure
senders, pressure indicators, piezometers and manometers, among other names.
Pressure sensors can vary drastically in technology, design, performance, application
suitability and cost. A conservative estimate would be that there may be over 50
technologies and at least 300 companies making pressure sensors worldwide.
There is also a category of pressure sensors that are designed to measure in a dynamic
mode for capturing very high speed changes in pressure. Example applications for this
type of sensor would be in the measuring of combustion pressure in an engine cylinder or
in a gas turbine. These sensors are commonly manufactured out of piezoelectric
materials such as quartz.
Some pressure sensors, such as those found in some traffic enforcement cameras,
function in a binary (off/on) manner, i.e., when pressure is applied to a pressure sensor,
the sensor acts to complete or break an electrical circuit. These types of sensors are also
known as a pressure switch.
Types of pressure measurements
silicon piezoresistive pressure sensors
Pressure sensors can be classified in terms of pressure ranges they measure,
temperature ranges of operation, and most importantly the type of pressure they
measure. Pressure sensors are variously named according to their purpose, but the
same technology may be used under different names.
• Absolute pressure sensor
This sensor measures the pressure relative to perfect vacuum.
• Gauge pressure sensor
This sensor measures the pressure relative to atmospheric pressure. A tire pressure
gauge is an example of gauge pressure measurement; when it indicates zero, then the
pressure it is measuring is the same as the ambient pressure.
• Vacuum pressure sensor
This term can cause confusion. It may be used to describe a sensor that measures
pressures below atmospheric pressure, showing the difference between that low
pressure and atmospheric pressure (i.e. negative gauge pressure), but it may also be
used to describe a sensor that measures low pressure relative to perfect vacuum (i.e.
• Differential pressure sensor
This sensor measures the difference between two pressures, one connected to each side
of the sensor. Differential pressure sensors are used to measure many properties, such
as pressure drops across oil filters or air filters, fluid levels (by comparing the pressure
above and below the liquid) or flow rates (by measuring the change in pressure across a
restriction). Technically speaking, most pressure sensors are really differential pressure
sensors; for example a gauge pressure sensor is merely a differential pressure sensor in
which one side is open to the ambient atmosphere.
• Sealed pressure sensor
This sensor is similar to a gauge pressure sensor except that it measures pressure
relative to some fixed pressure rather than the ambient atmospheric pressure (which
varies according to the location and the weather).
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