Experiment-2.2 19BAM1037
Experiment-2.2 19BAM1037
Experiment-2.2 19BAM1037
Theory:
A pressure sensor measures the pressure, typically of gases or liquids. Pressure is an expression
of the force required to stop a gas or 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 are used in numerous ways for
control and monitoring in thousands of everyday applications. Pressure sensors can be used in
systems to measure other variables such as fluid/gas flow, speed, water level, and altitude.
Pressure sensors can alternatively called pressure transducers, pressure transmitters, pressure
senders, pressure indicators among other names.
Observations:
The Piezoresistive effect describes the change in electrical resistance that occurs when an
external force is applied to a semiconductor. This change only affects the material's electrical
resistivity. Unlike the piezoelectric effect, it cannot be used to generate a voltage across the
device. Pressure sensors can be classified in term of pressure ranges they measure, temperature
ranges of operation, and most importantly the type of pressure they measure. In terms of
pressure type, we can categorize them in four categories.
1. Vacuum pressure sensor: This sensor is used to measure pressure less than the
atmospheric pressure at a given location.
2. Absolute pressure sensor: This sensor measures the pressure relative to perfect Vacuum
pressure (0 PSI or no pressure). Atmospheric pressure, is about 100kPa (14.7 PSI) at sea
level. Atmospheric pressure is an absolute pressure.
3. Gauge pressure sensor: This sensor is used in different applications because it can be
calibrated to measure the pressure relative to a given atmospheric pressure at a given
location. An example of gauge pressure would be a type pressure gauge. When the type
pressure gauge reads 0 PSI, there is really 14.7 PSI (atmospheric pressure) in the type.
4. Differential pressure sensor: This sensor measures the difference between two or more
pressures introduced as inputs to the sensing unit. For example, measuring the pressure
drop across an oil filter. Differential pressure is also used to measure flow or level in
pressurized vessels.
1Kpa (Kilopascal)=0.145psi
Percentage error:
Learning outcomes: