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Difference between Sensor and Transducer

05 Feb 2019 7:41 am || 0

The questions related to the difference between sensor and transducer have always been a hot favorite with interviewers. One of the main differences between sensors and transducers is that while both are physical devices, the former sense physical quantities before converting them into signals; conversely, the latter is used for converting a specific form of energy into another.

In this article, we aim to define transducer and sensor and bring out the points of distinction between sensors and transducers via a chart simply depicting sensor vs. transducer pointers. Read on for more.

Transducer vs. Sensor

Sensors and transducers are physical devices that are used interchangeably. Used in electronic gadgets, appliances, and devices, transducers and sensors are different from each other in more ways than one.

Basis of difference Sensor Transducer
Meaning A sensor is designed to sense any physical change occurring in the surrounding. It is responsible for converting the transition into a precise quantity. A transducer actuates to transform energy from a given form to another.
Comprises of The sensor has no other component except itself. Signal conditioning and sensor form parts of the transducer.
Functionality Detects changes and generates corresponding electrical signals. Responsible for converting energy into a different form.
Applications A magnetic sensor, Accelerometer sensor, Proximity sensor, Light sensor, etc. Thermistor, Thermocouple, Potentiometer, etc.
A featured suggestion of the device The sensor suggests a user’s capacity to receive information regarding physical quantities that are not perceivable through human senses as these quantities are subliminal or extremely minute. The transducer suggests that the quantities sent to input and output devices are not the same.
Dependency A sensor may not be a transducer. A transducer will always contain a sensor.
Complexity of performance In comparison to a transducer, a sensor is less complicated in its performance. It directly transforms a given physical quantity into a different physical quantity (for example, resistance, capacitance, etc.). A transducer serves to be a more complicated device as it is designed to transform the physical quantity that is provided to the input part into another output signal (voltage, current, etc.). Thus, a transducer fuses the conditioning system and sensing elements to provide output signals that are proportional to input quantities.
Feedback A sensor measures a physical quantity only and cannot give input to the desired system on its own. A transducer is capable of converting between different forms of energy. It is generally used for providing feedback to the desired system through the output device after due processing takes place in the signal conditioning unit.

What is Sensor?

As per the definition of a sensor, it is a physical device that is useful for measuring the changes in the surroundings after measuring their physical quantities (light, heat, sound, etc.) and transforming them into signals (current, voltage, etc.) that can be easily read by users. Sensors provide accurate readings if the calibration is done correctly. For instance, mercury present in a thermometer transforms the body temperature change into easily measured reading that can be sighted through a calibrated glass tube; it does so because of its expansion and contraction courtesy temperature changes. Similarly,

  • Motion sensors are applied in home security systems as well as automation door systems.
  • Photosensor sense changes in infrared/ultraviolet light.
  • Accelerometer sensors are utilized in the mobile to detect screen rotations.
  • The primary input unit to a sensor is in the form of a transducer (generally referred to as the sensing element). However, a sensor is capable of including advanced circuitry for making it easy for users to deal with the interface connected to the end application.

What is Transducer?

As per the definition of a transducer, it is a physical device that alters the physical attributes of given non-electrical signals to form an electrical signal that can be measured easily. This process of conversion of energy in the transducer is referred to as transduction. Transduction takes two steps to complete; firstly, it senses signals and then strengthens them for the cause of further processing.

  • Transducers comprise three main components; these are signal conditioning/processing device, input device, and output device.
  • The input devices are designed to accept and measure quantities and send them as proportional analog signals to processing/ conditioning devices.
  • The conditioning device then modifies filters and sends the signal to output devices in an easily-understandable format.
  • A transducer is also capable of converting electrical signals into physical quantities for the sake of creating an actuator. As soon as this process takes place, the transducer ceases to be a sensor. For instance, a piezoelectric transducer is capable of being used for sensing and actuation purposes.

A key difference between transducer and sensor

  • The sensor senses the physical changes in the form of precise quantities to users. On the other hand, a transducer is used for transforming a specific kind of energy into a different format.
  • The sensor does not have any other component for sensing/ processing purposes, while a sensor and signal conditioning unit are used for making a transducer work.
  • The sensor primarily functions to sense physical changes in the environment; on the other hand, a transducer is used for converting physical quantities into electrical signals.
  • The examples of sensors are a barometer, gyroscope, accelerometer, etc. The thermocouple, thermistor, antennas, etc. are examples of transducers.

Conclusion

Sensors and transducers are used for measuring physical quantities such as temperature, light, displacement, heat, etc. These physical devices are quite diverse in nature and functionality and should not be confused in any way. We have tried to touch upon the various points of difference between sensors and transducers in this article. In case you have any further queries or inputs, then please drop us a line in the comments section below- we shall get back to you at the earliest.