The basic difference between a transducer and a sensor is that a transducer transforms energy from one form to another, like converting mechanical energy to electrical signals. In comparison, a sensor identifies specific inputs such as light, temperature, pressure, or motion and translates them into measurable outputs.
What Is a Transducer?
A transducer is an electronic device that transforms the energy from one form to another. It converts an input signal from a sensor into a usable direct current or voltage for easy measurement.
Examples
Microphones (input transducer) and loudspeakers (output transducer), with sensors serving as input devices and actuators as output devices.
Input transducer
An input transducer, or sensor, transforms physical energy into a readable signal. For instance, a microphone converts sound waves into an electrical signal, allowing transmission through wires to an amplifier.
Output transducer
An Output transducer, also known as an actuator, reverses the process of an Input transducer by transforming electrical signals into a different form of energy. For instance, a lamp changes electricity into light, while a motor converts electricity into motion.
What Is Sensor?
A sensor is a device designed to detect changes in physical quantities or energy in the surrounding environment. It responds to stimuli, such as heat, light, pressure, humidity, or motion, generating a non-electrical signal. The output signal from a sensor is often not directly readable and requires further processing, such as amplification, attenuation, or conversion through an electronic circuit to become a readable signal.
Take a mercury thermometer, for instance; the liquid metal expands with rising temperature, serving as a temperature sensor. Yet, the output is not immediately readable without a specific scale. Similarly, a thermistor’s resistance varies with temperature changes, providing a sensor output that requires interpretation.
Transducer vs Sensor
The major difference between the transducer and the sensor is given below:
| Basis of Difference | Sensor | Transducer |
| Definition | A device converting physical parameters to electrical output. | Generally provides feedback through the output device after processing. |
| Main components | Consists only of itself. | Comprises input device (sensor), processing device (signal conditioning), and output device. |
| Dependency | Not all sensors are transducers. | A sensor is part of all transducers. |
| Complexity | Less complicated construction and processing. | Relatively more complex due to energy transformation. |
| Function | A device that transform energy from one form to another. | Converts energy into a different form. |
| Feedback | Does not provide feedback to the system. Only measures changes. | A device that transforms energy from one form to another. |
| Examples | Temperature sensor, photo sensor, proximity sensor, etc. | Strain gauge, microphone, loudspeaker, piezoelectric element, etc. |