Low pressure transducers for air and non-corrosive gases low pressure measurement.

Low pressure transducers for air and non-corrosive gases low pressure measurement.

Low pressure transducers also called low pressure transmitters. Sino-Inst offers High-precision low-pressure pressure transducers. 0 ~ 2.5kPa to 0 ~ 30kPa measurable. Low pressure transducer converts the measured pressure into an accurate electrical signal. This process is achieved through a high-performance amplifier circuit. The unique design of this product makes it unique in terms of environmental resistance. It is less affected by temperature changes. Anti-vibration With good long-term stability. Low pressure tranducers are suitable for applicaitons like: Liquid level. Flood warning. Waste water. Clean room. And open channel flow applications.

Sino-Inst offers a variety of low pressure transducers for industrial pressure measurement. If you have any questions, please contact our sales engineers.


Sino-Inst SI-303 series high-precision low-pressure pressure transmitters adopt internationally renowned brand sensors. The measured pressure is converted into accurate electrical signals through high-performance amplifying circuits.

The unique design of this product makes it resistant to environmental influences Unique play. Little affected by temperature change. Vibration resistance and good long-term stability. It is extremely suitable for engineering equipment, factory automation control and other fields.

Features of Low-Pressure Transmitter

SI-303 Low Pressure Transducer 1
SI-303 Low Pressure Transducer
  • Low range and high dynamic frequency response;
  • Full stainless steel housing, excellent corrosion performance;
  • Advanced temperature digital compensation function, wide working temperature range;
  • Using piezoresistive diffusion silicon chip. The natural frequency is higher than the piezoelectric dynamic pressure sensor (the natural frequency can reach 400kHz);
  • Good signal-to-noise ratio, high resolution, high signal-to-noise ratio, and strong anti-interference ability;
  • Small size, light weight, complete type, high cost performance;
  • Suitable for high-end measurement industries. Such as chemical explosion experiments, hydraulic engineering and aerodynamic experiments;

Specifications of SI-303 Low-Pressure Transducer

Measurement mediumNon-corrosive, dust-free, dry gas
Measuring range         0 ~ 2.5kPa to 0 ~ 30kPa
Overload pressure1.5 times the range
output signal           4 ~ 20mADC (two-wire system)
0 ~ 5VDC, 1 ~ 5VDC (three-wire system) 
Supply voltage range16 VDC ~ 32VDC (constant voltage)
Standard supply voltage24VDC (constant voltage)
Response time 1.0ms 1.0ms
Operating temperature          -20 ℃ ~ + 85 ℃
Compensation temperature0 ~ 70 ℃
Relative humidity          0 ~ 100% (non-condensing)
Load Resistance        (4 ~ 20mA): R = (U-16) /0.02-RD
Where: U is the power supply voltage and RD is the cable internal resistance 
Sum of linearity, hysteresis, and repeatability errors± 0.2% FS (typical value)
± 0.4% FS (maximum) 
Power ImpactLess than 0.02% / V of the output range
Zero temperature drift± 1.5% FS (± 0.2% level), ± 2% FS (± 0.4% level)
Full-scale temperature drift± 1.5% FS (± 0.2% grade), ± 2% FS (± 0.4% grade)
Long-term stability± 0.25% FS / year
ResolutionInfinite, limited only by output noise
Housing material       stainless steel
Process interfaceM20 × 1.5, M12 × 1
Or special production according to user needs 
Leading methodDirect outlet, aviation plug, Hirschmann plug
Electrical parameters (voltage output type):Circuit: 3 wires
Power supply: 24VDC
Output: 0 ~ 5VDC or 1 ~ 5VDC 
Electrical parameters (current output type):Circuit: 2 wires
Power supply: 24VDC
Output: 4-20mA 

Read more about: Common Units Of Pressure

Applications of Low pressure transducers

  • Developed for low pressure applications in general industry and OEM applications
  • Flow measurement
  • Room monitoring
  • Energy management
  • HVAC and VAV  
  • Process control
  • Aerospace
  • Car, medical equipment
  • Pipeline system

What is a low-pressure transducer?

Low pressure transducer is pressure transmitter based on piezoresistive pressure sensor. Low pressure transmitters are suitable for air and non-corrosive gases low pressure measurement.

Low pressure transmitters are suitable formeasuring low-level gauge, differential & absolute pressures. Low pressure transmitters with 4 to 20 mA current output, can measure low pressure below 1 bar (15 psi, 400 inWG or 1000 mbar).

Low-pressure transmitters are used to measure air ventilation pressures in buildings. And small pressure differences between two different locations. Such as clean rooms and laboratories where it is important to prevent air contamination.Low pressure ranges are required to measure small pressure values. Often between two locations where the air is being moved from one place to another.

Low range pressure measurement is required for monitoring and controlling ventilation, and air extraction in office and factory buildings. In building management applications, air movement in large spaces creates very small changes in air pressure. So it is necessary to use highly sensitive measurement devices, which are set to read in inches of water column, mbar, hPa or Pascals.

Read more about: Gas Pressure Transducer-Sensor for Gas Pressure Meaurement

How low-pressure transducers work?

Low pressure pressure transmitters use semiconductor piezoresistive effect and micro-machining technology.

On single crystal silicon wafers, semiconductor processes such as photolithography and diffusion are used to make Wheatstone bridges.

When subjected to external forces, micro-strains are generated. The electric bridge is out of balance. The signal is processed by a high-performance amplifying circuit. Makes the product have the advantages of high accuracy, good repeatability, high reliability, etc.

The circuit and core are all sealed in a stainless steel housing. And a variety of installation interfaces are designed.

For very low pressures, there are other types of transducers available, which are based on other principles. These include Pirani gauge, thermocouple and ionization gauge.

The first two techniques are based on the rate at which heat is loss from a heated filament placed in the low-pressure environment. This heat loss is depended on the number of gas molecules per unit volume.

  • Pirani gauge – This gauge calculates filament temperature by measuring filament resistance. Resistance measurement is measured with the help of a Wheatstone bridge circuit. The relation between the resistance and the applied pressure is highly non-linear.
  • thermocouple – In this type of pressure transducer, a thermocouple is attached to the heated filament to measure its temperature. For the reference temperature in the thermocouple, room temperature is used. The voltage output of the thermocouple varies non-linearly with the gas pressure.
  • Ionization gauge – It is highly useful for measuring very small pressures in the range of 10–3 atm to 10–13 atm. Here, the gas, whose pressure is to be measured, is ionized with the help of a heated filament. The current is measured between two electrodes in the ionized region, which depends on the gas pressure, because the number of ions per unit volume depends on the gas pressure.


What is the function of a pressure transducer?

pressure sensor is a device for pressure measurement 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.
More about Pressure sensor Wikipedia.

How does a 3 wire pressure transducer work?

Three-wire system: The three-wire sensor is the separation of the positive terminal of the power supply and the positive terminal of the signal output, but they share a COM terminal.
Use one wire for the positive end of the power supply and one wire for the positive end of the signal output. The negative end of the power supply and the negative end of the signal share one line. Its power supply is mostly 24v.dc, the output signal is 4-20ma.dc, the load resistance is 250ω or 0-10ma.dc, and the load resistance is 0-1.5kω; some also have ma and mv signals, but the load resistance or input The resistance varies with the form of the output circuit. The designation of a few-wire system was only after the birth of the two-wire transmitter. This is the result of the extensive application of electronic amplifiers in meters. The essence of amplification is an energy conversion process, which is inseparable from power supply. So the first to appear is a four-wire transmitter; that is, two wires are responsible for the power supply, and the other two wires are responsible for outputting the amplified signal (such as voltage, current, etc.).
How is a 3 wire 4-20mA pressure transmitter connected electrically?
Example of Sensor Connections:
Volts Input + (Supply positive)
Current Output + (Signal positive)
Volts Input (negative) / Current Output (Supply negative)
Connecting a 3 wire pressure transmitter

How do you hook up a pressure transducer?

Pressure sensors are generally two-wire, three-wire, four-wire, and some are five-wire.
Pressure sensor two-wire system is relatively simple. General customers know how to connect. One line is connected to the positive pole of the power supply. The other line is the signal line connected to the negative pole of the power supply through the instrument. This is the simplest. A wire is added to the wire system. This wire is directly connected to the negative pole of the power supply, which is a bit more troublesome than the two-wire system.
The four-wire pressure sensor must have two power input terminals and the other two signal output terminals. Most of the four-wire system is a voltage output rather than a 4-20mA output. The 4-20mA is called a pressure transmitter, and most of them are made of two-wire system.
Some of the signal output of the pressure sensor is not amplified, and the full-scale output is only tens of millivolts. Some pressure sensors have internal amplification circuits, and the full-scale output is 0 ~ 2V.
As for how to connect the display meter, it depends on the range of the meter. If there is a gear that is compatible with the output signal, you can directly measure it, otherwise you need to add a signal adjustment circuit. The five-wire pressure sensor is not much different from the four-wire system. There are relatively few five-wire sensors on the market.
ELECTRICAL CONNECTION prssure transducer

Sino-Instrument offers over 10 Low-Pressure Transducers.

About 50% of these are 4-20ma Low-Pressure Transducers. 40% are Differential Pressure Gauge. And 20% are Diaphragm Seal Pressure transmitters. 20% are 4-20ma differential pressure transmitters.

A wide variety of  Low-Pressure Transducers options are available to you, such as free samples, paid samples. 

Sino-Instrument is a globally recognized supplier and manufacturer of 
Low-Pressure Transducers, located in China.

The top supplying country is China (Mainland), which supply 100% of 
Low-Pressure Transducers respectively.

Sino-Instrument sells through a mature distribution network that reaches all 50 states and 30 countries worldwide.

Low-Pressure Transducers products are most popular in Domestic Market, Southeast Asia, and Mid East. 

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

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