Difference Between Intrinsic And Extrinsic Sensors


What are Intrinsic Sensors?

Intrinsic sensors are devices that derive their measurements directly from the property or phenomenon being measured without relying on external references. They are designed to measure physical, chemical, or biological properties inherent to the system they are monitoring.

Types of Intrinsic sensors

  • Temperature Sensors: These sensors measure temperature variations directly without relying on external references. Examples include thermocouples, resistance temperature detectors (RTDs), and thermistors. They exploit the change in electrical resistance or voltage with temperature.
  • Pressure Sensors: Intrinsic pressure sensors measure pressure variations in gases or liquids directly. They can be based on various principles such as piezoelectric, capacitive, or resistive. These sensors find applications in industries like automotive, aerospace, and healthcare.
  • Strain Gauges: These sensors measure the deformation or strain in an object. They are often used in structural health monitoring, material testing, and geotechnical applications. Strain gauges operate on the principle that the electrical resistance of a material changes when it is strained.
  • pH Sensors: Intrinsic to chemical processes, pH sensors measure the acidity or alkalinity of a solution. They are used in industries like pharmaceuticals, food and beverage, and environmental monitoring.
  • Biometric Sensors: These sensors measure unique biological characteristics such as fingerprints, iris patterns, or facial features for identification and authentication purposes. They are extensively used in security systems, access control, and mobile devices.
  • Gas Sensors: Intrinsic gas sensors detect the presence or concentration of gases in the surrounding environment. These sensors can be based on principles like electrochemical, semiconductor, or optical absorption. They have applications in environmental monitoring, industrial safety, and indoor air quality control.

Extrinsic Sensors

Extrinsic sensors are devices used to measure physical quantities or environmental parameters outside of the system they are associated with. Unlike intrinsic sensors, which are integrated within a system or device, extrinsic sensors are typically standalone units that detect and measure external stimuli.

Types of Extrinsic Sensors

  • GPS Sensors: Global Positioning System (GPS) sensors determine the location of an object by receiving signals from satellites. They are widely used in navigation, mapping, and location-based services.
  • Accelerometers: Extrinsic accelerometers measure acceleration or changes in velocity relative to an external frame of reference, typically Earth’s gravity. They are used in applications such as motion sensing in smartphones, vehicle stability control systems, and inertial navigation systems.
  • Light Sensors: These sensors measure ambient light intensity or specific wavelengths of light. They are commonly found in smartphones, cameras, automatic lighting systems, and display brightness control.
  • Proximity Sensors: Extrinsic proximity sensors detect the presence or absence of nearby objects without physical contact. They are used in applications such as touchless switches, obstacle detection in robotics, and smartphone screen dimming during calls.
  • Humidity Sensors: Extrinsic humidity sensors measure the moisture content in the air. They find applications in weather monitoring, HVAC systems, industrial drying processes, and agricultural applications.
  • Magnetic Sensors: These sensors detect the presence, strength, or direction of magnetic fields. They are used in compasses, position sensing in automotive applications, and proximity detection in electronic devices.

Intrinsic And Extrinsic Sensors: Key Takeaway

BasisIntrinsic SensorsExtrinsic Sensors
Sensing PrincipleMeasure internal properties directlyMeasure external properties indirectly
ExamplesStrain gauges, thermistors, pH electrodesCameras, ultrasonic sensors, GPS
Contact RequirementRequire direct contact with the objectCan operate without direct contact
Sensing RangeMay have limited range depending on object sizeHave broader range
CalibrationMay require calibration for specific applicationsCalibration might be less frequent or unnecessary
SensitivityGenerally higher sensitivity for internal propertiesSensitivity can vary based on external conditions
Environmental ImpactLess susceptible to environmental interferenceMore susceptible to environmental interference
CostCan be costly due to integration complexityCost may vary based on technology and features