Difference between active sensor and passive sensor | active sensor vs passive sensor

This page compares active sensor vs passive sensor and mentions difference between active sensor and passive sensor. The definitions and examples of active sensor and passive sensor are mentioned.

Sensors are devices which convert physical variables into signal variables. They are transducers which convert one form of input energy to the other form of output energy.

Sensors are categorized into two broad types based on their interaction with their measurement environments.

Active Sensor

Definition: The sensors which add energy to measurement environment as part of measurement process are known as active sensors. These sensors transmit either RF (radio frequency) waves or acostic waves which are reflected back from the object and are received by the sensors and consecutively measured/analyzed. These sensors are used in Radar and SONAR systems.

Example of active sensor:
• Ultrasonic sensor
• Microwave Motion Sensor

Passive Sensor

Definition: The sensors which do not add energy to the measurement environment but may remove some energy during measurement process are known as active sensors.

Example of passive sensor:
• Passive infrared (PIR) motion sensor
• Thermocouple
• Pressure gauge

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