Difference between a Sensor and a Transducer

The terms “sensor” and “transducer” are often used to describe the same devices. “Linear sensor” and “linear transducer” refer to the same component and this is not necessarily incorrect terminology. However, in some cases, “sensor” and “transducer” have different meanings and there are some differences between the two.

The main difference between a sensor and a transducer is the output signal. Both a sensor and a transducer are used to sense a change within the environment they are surrounded by or an object they are attached to. However, a sensor will give an output in the same format and a transducer will convert the measurement into an electrical signal.

Characteristics of a sensor

Sensors are defined as a device which is used to measure a physical quality, for example, light, sound or temperature, and give the output in an easy-to-read format for the user.

For example, in a mercury thermometer the mercury simply expands when the temperature rises to give a reading to the user, there are no electrical inferences or changes. A thermistor also simply responds to the change in resistance due to the temperature change. Read our blog post 'Introduction to Sensors' to find out more about them.

Characteristics of a transducer

A transducer can measure similar qualities to a sensor but will convert the signal from one physical form to another meaning their input and output signals are not the same as each other. Transducers are sometimes referred to as energy converters.

There are different types of transducers - input transducers and output transducers. An input transducer takes a form of energy and converts it into an electrical signal. An output transducer takes electricity and converts it into another form of energy - for example, a light bulb takes electricity and converts it to light, or a motor converts electricity to motion.

Comparison between a sensor and a transducer

	Sensor	Transducer
Definition/ Function	Senses the change and gives readings in the same format that the signals are received. An additional device will be needed to convert the energy should this be required.	Senses a change, and transforms the energy from one form to another. Usually from non-electrical to electrical or vice versa.
Examples	Pressure switches, thermistors, mercury thermometers, and motion sensors.	Pressure transducer, cable extension transducer, linear transducer, microphone
Applications	Infrared toilet flushes, pressure level in oxygen tanks, patient monitoring.	Engine controls, HVAC monitoring, steering systems on vehicles, ramp or bridge lifting or positioning.

Sensors and Transducers from Variohm

At Variohm we specialise in sensors and transducers for all applications within many industries.

If you are looking for a sensor or a transducer, please take a look at the following product ranges;

Alternatively, contact us on 01327 351004 or sales@variohm.com.

Article published on: 23/01/2020

Article last updated on: 01/09/2022