In electrical engineering, the terms sensor and transducer are interchangeable. They are widely employed in electrical applications as well as other smart devices and gadgets. They’re generally at odds with one another.
Sensors and transducers transform physical quantities and energy from the environment into a readable signal or an electrical signal. They are used in automation and instrumentation to detect and measure a variety of physical quantities.
What is a Sensor?
A sensor is an electronic device that detects or feels changes in physical quantities or energy. It responds to stimuli in the environment by emitting a non-electrical signal. Heat, light, pressure, humidity, motion, and other electrical values can all be sensed by a sensor.
A sensor’s output signal isn’t always in a readable format. It is then amplified, attenuated, or converted into a readable signal using an electrical circuit.
The mercury in a thermometer is an example of a sensor. Mercury is a liquid metal that expands as the temperature rises. It can detect changes in temperature as well. However, until it is placed in a proper scale, it is unreadable. Similarly, the resistance (Resistor Color Code) of a thermistor fluctuates as the temperature changes.
A potentiometer, for example, is a sensor whose resistance fluctuates depending on the position of its knob. If you don’t provide voltage to the resistance, you won’t be able to read it. The change in resistance manifests itself as a shift in the electrical signal.
Key Features of Sensor
Sensors are described as a device that detects a physical property, such as temperature, light, or sound, and sends the result in a simple format that the user can understand. Sensors turn them into something useful. Therefore, sensors, when calibrated precisely, are far too precise instruments.
“Not all transducers may be considered to be sensors, but many sensors are transducers,” according to a generic definition in several textbooks. A thermistor, for example, is a sensor that reacts to temperature changes but does not transfer the energy into a different form than what was initially observed.
This thermistor is a sensor on its own, but when integrated with a larger circuit or schematic, it becomes a transducer’s major component.
Another example is a mercury thermometer; when the temperature rises, the mercury expands readily, sending a reading format to the user. There are no symptoms or alterations in the electrical system. As a result, it started out as a sensor.
Sensors Application
The sensors used in the electronic industries have a variety of uses, some of which are listed below:
In businesses and homes, photosensors detect UV or infrared light.
Motion sensors are used in building security systems as well as automation door devices.
The mobile phone’s accelerometer sensors are used to detect the rotation of the screen.
What is a Transducer?
A transducer is a device that transforms one kind of energy into another. An electrical transducer, on the other hand, transforms various sources of energy into electrical signals. The process of converting energy is known as transduction.
A sensor and a signal conditioning unit are the two components of a transducer. A non-electric signal is generated when the sensor senses a change in the physical surroundings. The signal conditioning device turns the signal to an electrical signal and amplifies, attenuates, or processes it to make it legible.
A pressure transducer is an example of a transducer since it turns the applied pressure or stress into an electrical signal. It consists of two oppositely charged plates, one of which is fixed and the other of which is moveable. The capacitance in-between fluctuates as pressure is applied to the moving plate. The applied voltage fluctuates as the capacitance changes. As a result, the pressure becomes an electrical signal.
Key Features of Transducer
A transducer, like a sensor, may detect comparable values but converts the physical signal into a different format. It indicates that the output and input signals are not identical. Transducers are used as energy converters on occasion. Thermal, electrical, chemical, mechanical, magnetic, and radiation measurements are among the six categories of measurements available.
Input and output transducers are two types of transducers that can be used. An input transducer accepts a kind of energy and converts it to electrical output, whereas an output transducer receives electricity and converts it to a different type of energy. This approach is demonstrated via light bulbs and motors. The first is used to convert electricity to light, while the second is used to convert electricity to motion.
Differences between Sensor and Transducer
Aside from their names, sensors and transducers vary in a number of ways. One of the major distinctions between them is that sensors detect physical fluctuations in the environment, whereas transducers convert physical and nonelectrical values into an electrical signal. Other discrepancies between the transducer and the sensor are discussed in further detail in the following comparative data.
There are several significant variations between sensors and transducers. The most important of them are listed below:
The sensor is the most important component of the sensor circuit, and the transducer diagram is dominated by this sensor and its signal conditioner.
The sensor just detects physical differences in the environment, but the transducer may convert one type of physical quantity into another, such as an electrical signal. The thermocouple is a classic example of a transducer, whereas the barometer, gyroscope, and accelerometer are popular examples of sensors. A sensor detects or senses physical quantities in its environment, whereas a transducer transforms one type of energy into another.
And a sensor is a component in and of itself, but a transducer includes a sensor as well as a signal conditioning device. Meanwhile, a sensor does not have to have a transducer, but a transducer must have a sensor.
A sensor’s output may or may not be an electrical signal, whereas a transducer’s output is an electrical signal.
A sensor produces an analog output signal in real time, but a transducer may produce both analog and digital electrical signals.
A sensor cannot be directly linked to other systems, although a transducer can.
Comparison for a Selection
Finally, let’s look at how we’ll use the above guidelines to choose the best temperature sensor. Here’s a quick comparison of the LM35 and DHT11 based on the points mentioned above.
The LM35 is an analog temperature sensor that measures temperature using an electrical signal that changes with it. The temperature range for this sensor is -55 to 150°C, with a scale factor of.01V/°C. If the temperature is 30 degrees Celsius, the output voltage will be 0.3 volts. It does not require additional calibration and maintains an accuracy of 0.4°C for building temperature and 0.8°C for temperature beyond the range of 0°C to 100°C.
The DHT11 is a moisture and temperature sensor that is digital. The operating temperature range is 0 to 50°C, with a temperature sensing precision of 2°C. It has a 20 to 80 percent accuracy range, with a 5 percent inaccuracy for moisture detection, and a 1Hz sample rate.
Now that we’ve seen that the LM35 has a wider variety of functions than the DHT11, we can see that they can both be used in a residential application. We can, however, choose LM35 for more precise findings. Otherwise, DHT11 is a better alternative for controlling humidity with temperature.
Conclusion
However, the terms sensor and transducer are interchangeable; sensor refers to physical devices that only sense or detect physical quantities or changes in them. A transducer, on the other hand, is a device that converts one kind of energy into another. A sensor is a sub-component of a transducer, while a transducer is a general phrase. As a result, we may claim that all sensors are transducers, but not vice versa.
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