Pressure sensor
From Wikipedia, the free encyclopedia
A pressure sensor measures the pressure, typically of fluids. 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 generates a signal related to the pressure imposed. Typically, such a signal is electrical, but it might also include additional means, such as optic signals, visual signals and/or auditory signals.
Pressure sensors have particular utility for monitoring the pressure in a fluid network. As compared with flow sensors, pressure sensors often require less cost to achieve a similar result. Pressure sensors are often fabricated using thin membranes that flex under pressure.
Some pressure sensors function in a binary manner, i.e., when pressure is applied to a pressure sensor, the sensor acts to complete or break an electical circuit. Some speed cameras use them.
[edit] Types of fluid pressure measurements
Absolute Pressure
Absolute pressure is expressed relative to a vacuum (i.e., no pressure). Atmospheric pressure, is about 100kPa (14.7 psia) at sea level. Atmospheric pressure is an absolute pressure.r
Gauge Pressure
Gauge pressure is expressed relative to atmospheric pressure.
A vented gauge pressure sensor has one port uncovered so it may operate to sense the local atmospheric pressure. A sealed gauge pressure sensor has one port sealed at manufacture at average atmospheric pressure.
An example of gauge pressure would be a tire pressure gauge. When the tire pressure gauge reads 0 psig, there is really 14.7 psia (atmospheric pressure) in the tire.
Differential Pressure
A
