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We are surrounded by electronic devices of any kind, but have you ever wondered how they know exactly what they have to do and when they have to do it in order to work properly?
From smartphones to refrigerators, from computers to entire power stations, in every field of electronics, what makes circuits work properly are Sensors, devices that acquire information from the outside world and transmit it to circuits in the form of electrical signals.
In this video we will see how sensors and transducers work, devices used to translate physical quantities into easier information to read on displays, a fundamental requirement in any technological field.
Jaes has been in the industrial supply business for over 10 years and has become partner of some of the most important companies in the industrial automation market by supplying every type of sensor and transducer.
Sensors and transducers are able to acquire information from the outside, and they are commonly classified according to the type of physical quantity they measure, for example:
- a microphone is a sound sensor
- a thermocouple is a temperature sensor
- a photodiode is an optical sensor
- a pressure meter is a pressure sensor
and etc.
Physical quantities are all the properties of a phenomenon or a body that can be measured, and so can be expressed quantitatively by a number.
Sensors and Transducers, after detecting the values of a physical quantity, transform its variations into electrical signals.
So what is the difference between Sensors and Transducers?
Sensors are divided into Active or Passive.
Active Sensors are able to transform a physical quantity directly into an electrical signal without needing an external power supply.
Passive sensors, on the other hand, do not produce an electrical signal that can be used immediately; instead, they must be accompanied by powered electronics that will produce the correct electrical signal. The union of these two components is the Transducer.
These signals are then transmitted to a controller, which reads and interprets them.
Standard electrical signals are a range of electric tension (typically 0 to 5 volts, or 0 to 10 volts), or electric current (usually 4 to 20 milliamps).
Now, let’s see the various parameters that Sensors and Transducers can have.
First of all is the one called ’transfer function’:
Sensors and Transducers have an input signal and an output signal. The output signal varies as the input signal changes and is related to it by a mathematical function called the ’transfer function’.
The ’transfer function’ can be linear, quadratic, cubic, exponential or logarithmic. The most commonly used transducers either have a linear transfer or are operated in the range where the transfer is more linear. Linearity is, in fact, another important parameter that measures the nonlinearity error of the transfer function.
Another primary parameter is the Dynamic Range (also known as the functioning range). Which is the range of input values that the transducer or sensor can operate without damage.
The maximum value of the dynamic range identifies the range of the transducer. Whereas the minimum value designates the Resolution.
A good sensor or transducer has a low resolution (i.e. it can detect signals of small value) and a high range, so as to have a very large dynamic range.
Another crucial property is Sensitivity:
The sensitivity of the transducer, is the relation between the variation of the output magnitude, and that of the input which determined it.
From smartphones to refrigerators, from computers to entire power stations, in every field of electronics, what makes circuits work properly are Sensors, devices that acquire information from the outside world and transmit it to circuits in the form of electrical signals.
In this video we will see how sensors and transducers work, devices used to translate physical quantities into easier information to read on displays, a fundamental requirement in any technological field.
Jaes has been in the industrial supply business for over 10 years and has become partner of some of the most important companies in the industrial automation market by supplying every type of sensor and transducer.
Sensors and transducers are able to acquire information from the outside, and they are commonly classified according to the type of physical quantity they measure, for example:
- a microphone is a sound sensor
- a thermocouple is a temperature sensor
- a photodiode is an optical sensor
- a pressure meter is a pressure sensor
and etc.
Physical quantities are all the properties of a phenomenon or a body that can be measured, and so can be expressed quantitatively by a number.
Sensors and Transducers, after detecting the values of a physical quantity, transform its variations into electrical signals.
So what is the difference between Sensors and Transducers?
Sensors are divided into Active or Passive.
Active Sensors are able to transform a physical quantity directly into an electrical signal without needing an external power supply.
Passive sensors, on the other hand, do not produce an electrical signal that can be used immediately; instead, they must be accompanied by powered electronics that will produce the correct electrical signal. The union of these two components is the Transducer.
These signals are then transmitted to a controller, which reads and interprets them.
Standard electrical signals are a range of electric tension (typically 0 to 5 volts, or 0 to 10 volts), or electric current (usually 4 to 20 milliamps).
Now, let’s see the various parameters that Sensors and Transducers can have.
First of all is the one called ’transfer function’:
Sensors and Transducers have an input signal and an output signal. The output signal varies as the input signal changes and is related to it by a mathematical function called the ’transfer function’.
The ’transfer function’ can be linear, quadratic, cubic, exponential or logarithmic. The most commonly used transducers either have a linear transfer or are operated in the range where the transfer is more linear. Linearity is, in fact, another important parameter that measures the nonlinearity error of the transfer function.
Another primary parameter is the Dynamic Range (also known as the functioning range). Which is the range of input values that the transducer or sensor can operate without damage.
The maximum value of the dynamic range identifies the range of the transducer. Whereas the minimum value designates the Resolution.
A good sensor or transducer has a low resolution (i.e. it can detect signals of small value) and a high range, so as to have a very large dynamic range.
Another crucial property is Sensitivity:
The sensitivity of the transducer, is the relation between the variation of the output magnitude, and that of the input which determined it.
The instrument will be very sensitive when, for the same variation in the input variable, the variation in the output is very high.
Frequency, on the other hand, is the time taken by the transducer to transform the variation of the input magnitude into the output signal. It is important to note that the smaller the size of a sensor, the faster its response tends to be.
Let’s see some practical examples to understand how they work.
Let’s say, for example, that we want to monitor the pressure of a pipe: it ranges between 50 and 150 PSI, which we can approximate in the International System of Units to 345 and 1035 kPa [kilopascals].
A transducer detects the pressure in the pipe by its sensor, in this case a diaphragm, which sends an analogue electronic signal of a few millivolts to the transducer.
The pressure transducer (suitably calibrated to the minimum and maximum pressure range) linearises, compensates and expands the signal, which in this case is a range between 4mA and 20mA [milliamps].
The signal is sent to the programmable logic controller (PLC), that is, a computer that interprets the current at 20mA in a pipe pressure of 150 PSI or 1035 kPa, 4 mA in 50 PSI or 345 kPa, and, for example, 12 mA in 100 PSI or 690 kPa (i.e. 50% of the pressure range).
Now the controller can determine the pressure and, if necessary, it changes it by sending a signal to an actuator, which controls a pressure regulator.
In our second example we’ll examine the main components of a smartphone, during a phone call.
When we start a phone conversation, our voice is recorded by a microphone.
The microphone is nothing but a transducer capable of converting sound pressure waves into electrical signals.
Once the wave of our voice is converted into an electrical signal, it is received by a microelectromechanical system (MEMS), which interprets it into a binary code of many zeros and ones, digitising it.
In this way, our voice can be easily stored and eventually sent to the antenna.
Another example is the thermocouple, a temperature transducer.
It is a probe consisting of 2 wires made of different metals, where one extremity called the HOT JUNCTION, is placed in the environment to be measured. While the other extremity, called the COLD JUNCTION, is connected to a measuring instrument.
The heat difference between the two extremities generates a displacement of electrons in the cooler part, creating an electric potential difference with a specific voltage, from which the measuring instrument can interpret the temperature.
Let’s now see a rotary encoder, known as an angle transducer.
We can see that on the inside there is a slotted disc placed on the rotating shaft, used together with light sources and fixed photo sensors, usually photodiodes. As the shaft rotates, light sources illuminate the coding disc, and the transmitted light that manages to pass through the grooves meets optical sensors capable of producing (with output signals) a unique code pattern, which determines the exact position of the shaft.
A PLC ’Programmable Logic Controller’ is always required to interpret sensor and transducer signals.
If you are interested in understanding how PLCs and DCS work, please watch our previous videos.
If you’ve found this video useful, let us know by leaving a like and a comment, you can also share it, and don’t forget to subscribe to our channel.
Frequency, on the other hand, is the time taken by the transducer to transform the variation of the input magnitude into the output signal. It is important to note that the smaller the size of a sensor, the faster its response tends to be.
Let’s see some practical examples to understand how they work.
Let’s say, for example, that we want to monitor the pressure of a pipe: it ranges between 50 and 150 PSI, which we can approximate in the International System of Units to 345 and 1035 kPa [kilopascals].
A transducer detects the pressure in the pipe by its sensor, in this case a diaphragm, which sends an analogue electronic signal of a few millivolts to the transducer.
The pressure transducer (suitably calibrated to the minimum and maximum pressure range) linearises, compensates and expands the signal, which in this case is a range between 4mA and 20mA [milliamps].
The signal is sent to the programmable logic controller (PLC), that is, a computer that interprets the current at 20mA in a pipe pressure of 150 PSI or 1035 kPa, 4 mA in 50 PSI or 345 kPa, and, for example, 12 mA in 100 PSI or 690 kPa (i.e. 50% of the pressure range).
Now the controller can determine the pressure and, if necessary, it changes it by sending a signal to an actuator, which controls a pressure regulator.
In our second example we’ll examine the main components of a smartphone, during a phone call.
When we start a phone conversation, our voice is recorded by a microphone.
The microphone is nothing but a transducer capable of converting sound pressure waves into electrical signals.
Once the wave of our voice is converted into an electrical signal, it is received by a microelectromechanical system (MEMS), which interprets it into a binary code of many zeros and ones, digitising it.
In this way, our voice can be easily stored and eventually sent to the antenna.
Another example is the thermocouple, a temperature transducer.
It is a probe consisting of 2 wires made of different metals, where one extremity called the HOT JUNCTION, is placed in the environment to be measured. While the other extremity, called the COLD JUNCTION, is connected to a measuring instrument.
The heat difference between the two extremities generates a displacement of electrons in the cooler part, creating an electric potential difference with a specific voltage, from which the measuring instrument can interpret the temperature.
Let’s now see a rotary encoder, known as an angle transducer.
We can see that on the inside there is a slotted disc placed on the rotating shaft, used together with light sources and fixed photo sensors, usually photodiodes. As the shaft rotates, light sources illuminate the coding disc, and the transmitted light that manages to pass through the grooves meets optical sensors capable of producing (with output signals) a unique code pattern, which determines the exact position of the shaft.
A PLC ’Programmable Logic Controller’ is always required to interpret sensor and transducer signals.
If you are interested in understanding how PLCs and DCS work, please watch our previous videos.
If you’ve found this video useful, let us know by leaving a like and a comment, you can also share it, and don’t forget to subscribe to our channel.