Pressure sensors are widely used to measure and monitor the pressure of gases and liquids in industrial equipment, HVAC systems, automotive systems, medical devices, process control, and IoT applications.
Choosing the right pressure sensor requires more than matching a pressure range. The measurement type, pressure range, accuracy, media compatibility, output signal, operating temperature, and mechanical connection can all affect sensor performance and system reliability.
This guide introduces the main types of pressure sensors, explains the key specifications to consider, and provides a practical selection process for different applications.
What Is a Pressure Sensor?
A pressure sensor detects the pressure of a gas or liquid and converts it into an electrical signal that can be measured, monitored, or processed by a control system.
Pressure sensors are commonly used for:
- Pressure monitoring
- Flow and process control
- Hydraulic and pneumatic systems
- HVAC equipment
- Automotive systems
- Medical equipment
- Industrial automation
- Water and fluid management
- IoT and remote monitoring
Depending on the sensor design, the output may be a resistance change, analog voltage, analog current, or digital signal.
Main Types of Pressure Sensors
Pressure sensors can be classified according to how pressure is measured and how the sensor is constructed.
Gauge Pressure Sensors
Gauge pressure sensors measure pressure relative to atmospheric pressure.
For example, a pressure reading of 2 bar means the measured pressure is approximately 2 bar above the surrounding atmospheric pressure.
Gauge pressure sensors are commonly used in:
- Hydraulic systems
- Pneumatic equipment
- Pumps
- Compressors
- Industrial machinery
- HVAC systems
They are suitable when the application needs to know how much pressure exists above or below atmospheric pressure.
Absolute Pressure Sensors
Absolute pressure sensors measure pressure relative to a vacuum reference.
They are useful when atmospheric pressure changes should not affect the measurement.
Typical applications include:
- Barometric measurement
- Vacuum systems
- Altitude measurement
- Automotive systems
- Environmental monitoring
Absolute pressure is often used when the actual pressure relative to a fixed reference is important.
Differential Pressure Sensors
Differential pressure sensors measure the difference between two pressure points.
Instead of measuring pressure relative to atmospheric pressure or vacuum, they compare:
Pressure at Port 1 − Pressure at Port 2
They are commonly used for:
- Airflow measurement
- Filter monitoring
- HVAC systems
- Flow measurement
- Industrial process control
- Liquid level measurement
For example, a differential pressure sensor can monitor the pressure difference across an air filter to determine whether the filter is becoming blocked.
Sealed Gauge Pressure Sensors
Sealed gauge sensors use a sealed reference pressure rather than directly referencing the current atmospheric pressure.
They can be useful in applications where atmospheric pressure changes need to be isolated from the measurement.
The appropriate pressure reference depends on the measurement system and application requirements.
Pressure Sensor Technologies
Pressure sensors can also be distinguished by their sensing technology.
Piezoresistive Pressure Sensors
Piezoresistive sensors detect changes in electrical resistance caused by mechanical deformation of a sensing element.
They are widely used because they can provide good sensitivity and are suitable for many pressure measurement applications.
Common applications include:
- Industrial equipment
- Automotive systems
- Medical devices
- HVAC
- Fluid monitoring
MEMS Pressure Sensors
MEMS pressure sensors use microelectromechanical structures to detect pressure changes.
They are typically compact and suitable for electronic systems where small size and low power consumption are important.
Common applications include:
- Smartphones and portable devices
- IoT equipment
- Barometric measurement
- Automotive electronics
- Embedded systems
Capacitive Pressure Sensors
Capacitive pressure sensors detect pressure-related changes in capacitance.
They can provide high sensitivity and are used in applications ranging from low-pressure measurement to industrial sensing.
The appropriate technology depends on the pressure range, accuracy, environment, and required electrical interface.
Pressure Sensor Types Compared
| Pressure Type | Reference | Typical Applications | Key Considerations |
| Gauge | Atmospheric pressure | Hydraulic, pneumatic, HVAC | Atmospheric pressure is the reference |
| Absolute | Vacuum | Barometric, automotive, vacuum systems | Independent of atmospheric pressure changes |
| Differential | Second pressure port | HVAC, airflow, filters, flow measurement | Requires two pressure inputs |
| Sealed Gauge | Sealed reference | Industrial and automotive applications | Reference pressure is fixed |
The pressure reference is one of the first specifications to determine when selecting a pressure sensor.
Key Pressure Sensor Specifications
Pressure Range
Pressure range is one of the most important specifications.
For example:
0–10 bar
or:
-1 to +1 bar
The selected sensor should cover the expected minimum and maximum pressure.
It is also important to distinguish between:
- Operating pressure
- Measurement range
- Overpressure
- Burst pressure
A sensor may tolerate a pressure above its rated measurement range for a limited period, but this does not mean it should be used continuously at that pressure.
Pressure Type
Determine whether the application requires:
- Gauge pressure
- Absolute pressure
- Differential pressure
- Sealed gauge pressure
Choosing the wrong reference type can result in incorrect measurements even when the pressure range appears suitable.
Accuracy
Accuracy indicates how close the measured pressure is to the actual pressure.
For example:
±1% FS
where FS means full scale.
When comparing pressure sensors, check whether the stated accuracy applies to the full operating range and whether other error sources, such as temperature effects, are included.
Overpressure and Burst Pressure
Pressure sensors may specify both overpressure and burst pressure.
Overpressure indicates how much pressure the sensor can withstand without permanent damage under specified conditions.
Burst pressure is a higher pressure level associated with structural failure limits.
These specifications are especially important in hydraulic, pneumatic, and industrial systems where pressure spikes may occur.
Output Type
Pressure sensors can provide different output signals, including:
- Analog voltage
- Analog current
- Digital output
- Resistance
Common industrial analog outputs include:
- 0–5 V
- 0–10 V
- 4–20 mA
Digital pressure sensors may use interfaces such as:
- I²C
- SPI
The output should be compatible with the connected MCU, ADC, PLC, or control system.
Supply Voltage
Check the sensor’s required supply voltage and current consumption.
Common supply voltages include:
- 3 V
- 5 V
- 12 V
- 24 V
For battery-powered or embedded applications, low-power operation may be an important consideration.
Media Compatibility
The pressure sensor must be compatible with the medium being measured.
The medium may be:
- Air
- Water
- Oil
- Refrigerant
- Gas
- Hydraulic fluid
- Other chemicals
Materials used in the pressure port, diaphragm, seals, and housing can affect compatibility.
This is particularly important when measuring corrosive, high-temperature, or chemically aggressive media.
Operating Temperature
Temperature can affect both sensor accuracy and reliability.
Check:
- Operating temperature
- Compensated temperature range
- Storage temperature
- Temperature coefficient
For industrial, automotive, and outdoor applications, the sensor should be evaluated under the actual expected temperature conditions.
Response Time
Response time indicates how quickly the sensor reacts to pressure changes.
A fast response may be important for:
- Pressure control
- Hydraulic systems
- Pneumatic systems
- Engine monitoring
- Rapidly changing processes
For slow-changing monitoring applications, an extremely fast response may not be necessary.
Mechanical Connection
The pressure port must match the system’s mechanical connection.
Consider:
- Thread type
- Port size
- Mounting method
- Tube connection
- Connector type
- Sensor dimensions
The mechanical interface should be checked carefully before selecting a specific product.
How to Choose the Right Pressure Sensor
A practical selection process can help narrow down suitable products.
Step 1: Identify the Measured Medium
Determine whether the sensor will measure:
- Air
- Water
- Oil
- Gas
- Refrigerant
- Hydraulic fluid
- Other media
Confirm that the sensor’s wetted materials are compatible with the medium.
Step 2: Determine the Pressure Type
Decide whether you need:
- Gauge pressure
- Absolute pressure
- Differential pressure
- Sealed gauge pressure
This should be determined before comparing individual products.
Step 3: Define the Pressure Range
Identify the minimum and maximum pressure expected during normal operation.
Also consider:
- Pressure spikes
- Overpressure
- Required safety margin
Avoid selecting a sensor whose rated range is only slightly above the normal operating pressure if significant pressure fluctuations are expected.
Step 4: Determine the Required Accuracy
Define the measurement accuracy required by the application.
For example:
- General monitoring may accept moderate accuracy.
- Process control may require higher accuracy.
- Precision measurement may require a tighter tolerance.
Consider temperature-related errors if the sensor will operate across a wide temperature range.
Step 5: Select the Output Type
Determine what the sensor needs to connect to.
For example:
- Analog voltage→ MCU ADC or analog control system
- 4–20 mA→ Industrial PLC or control system
- Digital interface→ MCU or embedded system
Make sure the output range is compatible with the receiving circuit.
Step 6: Check Electrical Requirements
Verify:
- Supply voltage
- Current consumption
- Output range
- Interface
- Electrical connection
This is particularly important when integrating the sensor into an existing control system.
Step 7: Check Media and Environmental Conditions
Consider:
- Fluid or gas type
- Temperature
- Humidity
- Vibration
- Corrosion
- Dust
- Water exposure
The sensor should be suitable for the complete operating environment, not just the pressure range.
Step 8: Confirm the Mechanical Interface
Finally, check:
- Pressure port
- Thread specification
- Mounting
- Package size
- Connector
- Installation space
A sensor that meets all electrical specifications may still be unsuitable if its mechanical interface does not match the system.
Pressure Sensors for Different Applications
Industrial Automation
Industrial systems commonly use pressure sensors for:
- Hydraulic pressure monitoring
- Pneumatic systems
- Process control
- Pump monitoring
- Compressor systems
Key selection factors include:
- Pressure range
- Accuracy
- Output type
- Overpressure rating
- Media compatibility
- Environmental protection
HVAC Systems
Pressure sensors can monitor:
- Refrigerant pressure
- Air pressure
- Filter pressure difference
- Duct pressure
Differential pressure sensors are particularly useful for airflow and filter monitoring.
Important factors include pressure range, accuracy, response time, and compatibility with the measured medium.
Automotive Systems
Pressure sensors are used in applications such as:
- Engine systems
- Tire pressure monitoring
- Fuel systems
- Air conditioning
- Intake and exhaust systems
Automotive applications may require wide temperature ranges, high reliability, and resistance to vibration.
Medical Equipment
Pressure measurement can be used in:
- Respiratory equipment
- Patient monitoring
- Medical pumps
- Blood pressure equipment
Accuracy, low pressure measurement capability, response time, and media compatibility can be important considerations.
IoT and Embedded Systems
IoT devices may use pressure sensors for:
- Environmental monitoring
- Barometric measurement
- Smart devices
- Remote equipment monitoring
Compact size, low power consumption, digital interfaces, and suitable pressure ranges are often important.
Common Pressure Sensor Selection Mistakes
Choosing Only by Pressure Range
A sensor may have the correct pressure range but still be unsuitable because of its pressure reference, output, accuracy, or media compatibility.
Confusing Gauge and Absolute Pressure
Gauge pressure and absolute pressure use different reference points.
A sensor designed for one measurement type may not provide the information required by an application using another.
Ignoring the Measured Medium
A sensor suitable for air may not necessarily be suitable for oil, refrigerant, or corrosive chemicals.
Always verify material compatibility.
Ignoring Pressure Spikes
Normal operating pressure may be within the sensor’s range, while sudden pressure spikes may exceed its overpressure capability.
Check the overpressure specification when pressure fluctuations are expected.
Ignoring Output Compatibility
A 4–20 mA sensor, 0–10 V sensor, and digital pressure sensor require different receiving circuits.
Make sure the output matches the control system.
Selecting an Incorrect Pressure Port
Thread type and port size must match the mechanical system.
Check the complete mechanical specification before purchasing.
Pressure Sensor Selection Example
Consider an industrial pneumatic system with the following requirements:
- Medium: Compressed air
- Pressure range: 0–10 bar
- Required accuracy: ±1% FS
- Supply voltage: 24 V DC
- Controller: Industrial PLC
- Output: 4–20 mA
- Continuous operation
A suitable selection process would be:
- Medium
The sensor must be compatible with compressed air.
- Pressure Type
If the system needs to measure pressure relative to atmospheric pressure, a gauge pressure sensor is appropriate.
- Pressure Range
Select a sensor with a suitable range covering 0–10 bar and sufficient margin for expected pressure fluctuations.
- Accuracy
Choose a sensor with accuracy of ±1% FS or better, depending on the actual system requirements.
- Output
Because the PLC accepts a 4–20 mA signal, select a pressure sensor with a compatible 4–20 mA output.
- Supply Voltage
The sensor should support the system’s 24 V DC supply.
- Mechanical Connection
Verify that the pressure port and thread match the pneumatic system.
This example shows that pressure sensor selection should begin with the medium, pressure reference, and system requirements, rather than simply searching for a sensor with the correct pressure range.
Pressure Sensor Selection at a Glance
| Application | Suitable Sensor Types | Key Selection Factors |
| Hydraulic Systems | Gauge | Range, accuracy, overpressure |
| Pneumatic Systems | Gauge | Range, output, response |
| HVAC Airflow Monitoring | Differential | Range, accuracy, response |
| Refrigerant Systems | Gauge, Absolute | Media compatibility, range, temperature |
| Barometric Measurement | Absolute | Accuracy, range, power |
| Industrial Process Control | Gauge, Differential | Accuracy, output, stability |
| IoT & Embedded Systems | Absolute, Gauge | Size, power, interface |
| Medical Equipment | Gauge, Differential | Accuracy, response, media compatibility |
Frequently Asked Questions
What are the main types of pressure sensors?
The main pressure reference types include gauge, absolute, differential, and sealed gauge pressure sensors. Pressure sensors can also use different sensing technologies, such as piezoresistive, capacitive, and MEMS technologies.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured relative to atmospheric pressure, while absolute pressure is measured relative to a vacuum reference.
What is a differential pressure sensor used for?
A differential pressure sensor measures the difference between two pressure points. It is commonly used for airflow measurement, filter monitoring, flow measurement, and HVAC systems.
How do I choose a pressure sensor?
Start by identifying the measured medium and pressure reference. Then determine the required pressure range, accuracy, output type, supply voltage, operating temperature, media compatibility, and mechanical connection.
What does 4–20 mA mean for a pressure sensor?
4–20 mA is a common analog current output used in industrial control systems. The current typically corresponds to the measured pressure range, making it suitable for transmission over relatively long cable distances and integration with PLCs and other industrial controllers.
Find the Right Pressure Sensor at LCSC
LCSC offers a wide selection of pressure sensors, including absolute pressure sensors, gauge pressure sensors, and differential pressure sensors for industrial automation, HVAC systems, automotive electronics, medical equipment, IoT devices, and other pressure monitoring applications. Compare products by key specifications such as pressure type, pressure range, accuracy, output type, supply voltage, response time, operating temperature, media compatibility, and pressure port to find a suitable solution for your application. Explore our pressure sensor selection or contact us for product recommendations and bulk purchasing support.
