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What is the difference between a transducer and a sensor

CELMI transducers are used in electronic engineering and computer devices. Their purpose is to convert the physical quantities and energy of their surroundings into an easily readable electrical or signal . They are used to sense and measure various physical quantities in automation and instrumentation.

Below we explain the difference between transducers and industrial sensors, but first, to be as precise as our measuring instruments, let’s see a little clarification.

Transducers or sensors? We’ll let you in on a pro secret

There is a difference between transducers and sensors, but in the industrial workplace – especially in the field of precision measurements – these two terms are used to indicate the same product, i.e. transducers like the ones you find among our proposals.

However, we want to be accurate in everything that concerns our work, so let’s see what a sensor is and what a transducer is.

What is a sensor?

A sensor is a physical device that detects or senses changes in any physical quantity or energy. It reacts to stimuli from its surroundings and delivers a non-electrical signal. A sensor can detect various types of electrical quantities such as heat, light, pressure, humidity, motion, etc.

The output signal of a sensor is not necessarily in a readable form, but is processed further: for example to amplify, attenuate or convert using an electronic circuit into a readable signal.

A practical example that we encounter in our daily lives and that can help us understand the concept of “sensor” is the mercury thermometer: mercury is a liquid metal that expands as the temperature increases. However, it is not readable unless placed within a specific scale. Similarly, the resistance of a thermistor changes as the temperature changes.

Main characteristics of the sensor

  • Detect changes in any physical quantity
  • The sensor is a component in itself and does not have a signal evaluation unit
  • Its output can be electrical in nature
  • Its output signal needs a scale or a processing circuit to make it readable

What is a transducer

A transducer is a physical device that converts one form of energy into another. The process of converting energy is called transduction.

A transducer is made up of two parts: a sensor and a signal conditioner. The sensor detects the change in the physical environment and generates a non-electrical signal. The signal conditioning unit converts the signal into electrical form and amplifies, attenuates, or processes it into a readable electrical signal.

An example of a transducer is a pressure transducer that converts applied pressure or stress into an electrical signal. It consists of two opposing charge plates, one fixed and the other movable. When pressure is applied to the movable plate, the receptive capacity varies and consequently the applied voltage. The pressure is converted into an electrical signal.

Let’s summarize the characteristics of the transducer:

  • converts one form of energy into another
  • consists of a sensor and a signal conditioner
  • it can convert non-electrical energy into electrical energy and vice versa
  • the output can be directly interfaced with another system
  • a transducer has a complex signal emission circuit

Still unsure about the difference between sensor and transducer?

In this table we have compared all the characteristics to clarify and better understand the difference between transducers and sensors:

A sensor is a device that detects a change in a physical environmentA transducer is a device that converts one form of energy into another.
A sensor is not necessarily a transducerEach transducer includes a sensor as a component
A sensor is itself a componentThe transducer is composed of a sensor and a signal emission circuit
The sensor converts physical quantities or energy into non-electrical signalsA transducer converts physical quantity or energy into an electrical signal
A sensor requires additional circuitry to process its output signal into a readable formA transducer does not require any processing circuitry. Its output is directly interfaced with a device or display
The output of a sensor is analog in natureA transducer can generate an analog and digital output
The output of one sensor can not be directly applied to any other systemThe output of a transducer can be connected directly to another system
A sensor requires no external power to operateA passive transducer requires an external power source to operate
A sensor can not be bidirectional, i.e. it only converts physical quantities into readable formA transducer is bi-directional. It can also convert electrical signal into physical quantities called inverse transducer
A sensor is a simple deviceA transducer has a complex electrical circuit used for energy conversion
Examples of sensors are thermometer, pressure sensor, ultrasonic sensor, light sensor, etc.Examples of transducers are pressure transducers, thermistor , potentiometer, piezoelectric transducer, Hall effect transducer, etc.


Now that the difference between transducers and sensors is clear, look at our proposals and remember: even if we call them sensors in technical jargon, they are real transducers .

Contact us now to speak with our technicians.