low pressure transducers

Single Pressure Connection, Ranges Down to 10 in w.c.

Low pressure transducer, also called low pressure transmitter.

With the flush diaphragm, can be used in the HVAC system.

SI-303 low pressure transducer can work as a pressure sensor,

for the differential pressure measurement, similar to the gems sensors.

What is a low-pressure transducer?

Low pressure transmitters with 4 to 20 milliamp current output,

for measuring low-level gauge, differential & absolute pressures 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.

Features of Low-Pressure Transmitter

SI-303 Low Pressure Transducer 1
SI-303 Low Pressure Transducer
  • Compact stainless steel construction with stainless steel sensor
  • Available in in/H2O to 25 psi
  • Wide range of mechanical and electrical connections
  • ±0.5% accuracy
  • NEMA 4X and 6P / IP65, IP67 and IP68
  • Customizable
  • Low range high accuracy provides precise control for process applications
  • Calibrated ratiometric output
  • Low voltage power requirement
  • Through holes allow for easy mounting to PCBs 

Specifications of SI-303 Low-Pressure Transducer

303-1-ALow pressure transducer, 0-10″ w.c., 4-20 mA output.
303-1-VLow pressure transducer, 0-10″ w.c., 0-5 VDC output.
303-2-ALow pressure transducer, 0-15″ w.c., 4-20 mA output.
303-2-VLow pressure transducer, 0-15″ w.c., 0-5 VDC output.
303-3-ALow pressure transducer, 0-25″ w.c., 4-20 mA output.
303-3-VLow pressure transducer, 0-25″ w.c., 0-5 VDC output.
303-4-ALow pressure transducer, 0-50″ w.c., 4-20 mA output.
303-4-VLow pressure transducer, 0-50″ w.c., 0-5 VDC output.
303-5-ALow pressure transducer, 0-100″ w.c., 4-20 mA output.
303-5-VLow pressure transducer, 0-100″ w.c., 0-5 VDC output.
303-6-ALow pressure transducer, 0-150″ w.c., 4-20 mA output.
303-6-VLow pressure transducer, 0-150″ w.c., 0-5 VDC output.
303-7-ALow pressure transducer, 0-200″ w.c., 4-20 mA output.
303-7-VLow pressure transducer, 0-200″ w.c., 0-5 VDC output.
303-8-ALow pressure transducer, 0-300″ w.c., 4-20 mA output.
303-8-VLow pressure transducer, 0-300″ w.c., 0-5 VDC output.
303-9-ALow pressure transducer, 0-400″ w.c., 4-20 mA output.
303-9-VLow pressure transducer, 0-400″ w.c., 0-5 VDC output.
Range range

Pressure type

gauge pressure, absolute pressure, sealing pressure

Power output

4 to 20 mA (12 to 30 VDC)
0 to 5V, 1 to 5V, 0.5 to 4.5V, 0 to 10V (12 to 24VDC)


0.5% FS

Hysteresis and repeatability


Temperature drift

1.5% FS (@-20 °C ~ 85 °C)

Response time

≤ 1ms (up to 90% FS)
Service life≥10x 10^6 
pressure cycle

Working temperature

-20 ° C ~ 85 ° C

Storage temperature

-40 ° C ~ 85 ° C

Medium temperature

-40~85°C (without heat sink)
-40~150°C (three heat sinks), -40°C~250°C (five heat sinks)

Insulation resistance


Vibration resistance

Sinusoidal: 20g, 25Hz~2kHz; IEC 60068-2-6
Random: 7.5grms, 5Hz ~ 1kHz; IEC 60068-2-64

Protection level


Media compatible

with a variety of media compatible with 316L stainless steel

Explosion-proof grade

Intrinsically safe explosion-proof ExiaIICT6

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

How low-pressure transducers work

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.

Natural gas pressure transducer

SMT3151 TGP -stainless steel sensor process, oil and gas industry_meitu_1
SMT3151 TGP -stainless steel sensor process, oil and gas industry

The Gauge Pressure Transmitter SMT3151 TGP,
has been specially designed for the process industry,
and measures vacuum, gauge and absolute pressure ranges of gases, steam, fluids, and dust up to 600 bar.

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 Transducersrespectively.

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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SI-303 Low-Pressure Transducer
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