Published on: Mar 4, 2016
Transcripts - Pressure transducers
Converts pressure into an analog electrical signal,
which is achieved by the physical deformation of
strain gages which are bonded into the diaphragm
of the pressure transducer and wired into a
wheatstone bridge configuration. Pressure
applied to the pressure transducer produces a
deflection of the diaphragm which introduces
strain to the gages. The strain will produce an
electrical resistance change proportional to the
pressure. One of the most common is the straingage base transducer.
The Electrical Output of Pressure
Pressure transducers are generally available
with three types of electrical output
Millivolt Output Pressure
• Are normally the most economical.
• The output is nominally around 30mV.
• The actual output is directly proportional to
the input power or excitation. If the
excitation fluctuates, the output changes.
• Because the output signal is so low, the
transducer should not be located in an
electrically noisy environment.
• The distances between the transducer and
the readout instrument should also be kept
Voltage Output Pressure Transducers
• Include integral signal conditioning which
provide a much higher output than a
• The output is normally 0-5Vdc or 0-10Vdc.
• Because they have a higher level output
these transducers are not as susceptible to
electrical noise as millivolt transducers and
can therefore be used in much more
4-20 mA Output Pressure Transducers
• Since a 4-20mA signal is least affected by
electrical noise and resistance & are best
used for long distances.
• It is not uncommon to use these transducers
in applications where the lead wire must be
1000 feet or more
Styles of Pressure Transducers
PC Board Mountable Pressure Transducers
are generally compact economical pressure
transducers designed to mount on an electrical
PC board and be integrated into other products
General Purpose Transducers
General purpose pressure transducers are the most
common since they are designed to fit the broadest
set of applications
Heavy Duty/Industrial Pressure
• Feature a much more rugged enclosure than other
• They are designed to accommodate heavy
• 4-20mA output provides much greater immunity
to electrical noise in industrial environments.
High Stability/High Accuracy
• An accuracy of 0.25% of full scale or higher.
• High stability and high accuracy can offer errors
as low as 0.05% of full scale
• Although more expensive than general purpose
transducers, they may be the only option if high
precision is required.
Flush Diaphragm Pressure
• With flush diaphragm pressure transducers, the
diaphragm is flush to the process. This eliminates a
cavity above the diaphragm that could collect fluid
matter from the process.
• Those applications include monitoring the pressure of
foods or liquids that have very high viscosity
Special Purpose Transducers
These include pressure transducers specially
designed for pressure measurement in very high or
low temperatures, submersible pressure
transducers, barometric pressure transducers and
pressure transducers with digital communications
output or wireless outputs.