Technical Blog

The Difference Between a Sensor and a Transducer

The words ‘sensor' and ‘transducer' are often used interchangeably although they are different devices with different characteristics.

The words ‘sensor' and ‘transducer' are often used interchangeably although they are different devices with different characteristics.

What is the difference between a sensor and a transducer? Sensors and transducers are both devices which react to a change in a physical quality in their surroundings.

The main difference between a sensor and a transducer is that a sensor senses the difference or change in the environment they are exposed to and gives an output in the same format where as a transducer takes a measurement in one form and converts it to another for example, a measurement which is not electrical and converts it into an electrical signal. This process is called â€transduction".

Transducers are sometimes referred to as sensors and vice versa - this can make telling the difference difficult.

What is a Sensor?

A Sensor is defined as a device which measures a physical quality (light, sound, space) and converts them into an easily readable format. If calibrated correctly, sensors are highly accurate devices. Not all transducers are sensors but most sensors are transducers.

For example a thermistor is a type of sensor; it will respond to the change in temperature but does not convert the energy into a different format to what it was originally sensed in.

What is a Transducer?

A transducer is an electronic device which converts energy from one form to another. There are six different types of measurements; mechanical, magnetic, thermal, electric, chemical and radiation, a transducer can take a measurement in one format and convert it to another. A thermistor on its own is a sensor but, when it is incorporated into a bigger circuit or device it will become an element of a transducer; for example, a thermometer is a transducer.

There are different types of transducer; an input transducer and an output transducer.

An input transducer takes measurement of a physical energy and converts it into a different signal to make it readable for a user. For example a linear transducer takes the positional measurement and converts it into electrical signals to give an output.

An output transducer is also known as an actuator. Output transducers work the opposite way to input transducers, they take electrical signals and convert them into another form. For example a light bulb can sometimes be referred to as an output transducer as it converts electricity into light.

Comparison between a Sensor and Transducer

Sensor

Transducer

Working principle

Senses a physical measurement and makes it readable for the user but keeps it in the same format

Senses the physical measurement and converts it from one form to another - eg: Non- electrical to electrical.

Examples

Thermistor, motion sensor, pressure switch

Microphones, pressure transducer, linear transducer.

Uses / applications

Patient monitoring, infrared toilet flushes, liquid dispensing in drinks machines.

HVAC monitoring, engine controls, steering systems, ramp and bridge lifting systems.



Sensors and Transducers from Positek

Here, at Positek we design and manufacture a wide range of displacement transducers. Find out about more of the products in our range;

For more information on our products or to discuss your application please contact us.

Article published on: 12/09/2019

Article last updated on: 12/09/2019