1. Discuss the Need for Sensors and highlight some of the charac-
teristics of Sensors.
NEED:-
• Sensors are omnipresent. They embedded in our bodies, automobiles, airplanes, cel-
lular telephones, radios, chemical plants, industrial plants and countless other appli-
cations.
• Sensors in industrial applications being used for process control, monitoring, and
safety, and in medicine being used for diagnostics, monitoring, critical care, and pub-
lic health.
• sensors for exploring space and improved environmental monitoring.
• Without the use of sensors, there would be no automation!
CHARACTERISTICS:-
Range : the difference between the maximum and minimum value of the sensed pa-
rameter
Resolution: The smallest change the sensor can differentiate.
Sensitivity: It is the ratio of change in output to a unit change of the input.
Error: Error is the difference between the result of the measurement and the true
value of the quantity being measured
Accuracy: It is the difference between measured value and true value
Precision: Precision is the ability to reproduce repeatedly with a given accuracy.
Repeatability: The ability of a sensor to give same output for repeated applications of
same input value.
Repeatability = (maximum – minimum values given) X 100 ⁄ full range.
Impedance: It is the ratio of voltage and current flow for sensor. For a resistive sensor,
the impedance Z is same as the
resistance R& its unit is ohms.
Response time: Response time is the amount of time required for a sensor to respond
completely to a change in input.
2. Explain the physical or chemical sensing principles of transduction.
,3. Explain with a neat diagram the components of measurement
system.
4.What is a Sensor? Briefly explain the classification of sensors.
SENSOR- A device that detects the changes in electrical or physical or other quantities
and thereby produces an output as an acknowledgement of change in the quantity is
called as a Sensor. Generally, this sensor output will be in the form of electrical or opti-
cal signal.
Classification of Sensors
Sensors can be ranked into various classification systems, but for the sake of sim-
plification, we have divided them into 5 core classifications.
1. Active and Passive Sensors
◦ Active Sensors (also known as parametric sensors) are sensors that
require an external power source to operate. Examples of active sen-
sors include GPS sensors and radar sensors.
◦ Passive Sensors (also called self-generated sensors) generate their
own electric signal and do not require any external power source. Ex-
amples of passive sensors include thermal sensors, electric field sens-
ing, and metal detecting.
2. Contact and Non-Contact Sensors
◦ Contact Sensors are those that require physical contact with their stim-
ulus. Familiar examples of contact sensors are temperature and strain
gauge sensors.
◦ Non-Contact Sensors, on the other hand, require no physical contact.
These types of sensors include optical and magnetic sensors, as well
as infrared thermometers.
, 3. Absolute and Relative Sensors
◦ Absolute Sensors mimic its name by providing an absolute reading of
its stimulus. For example, a thermistor always measures the exact, or
absolute, temperature reading.
◦ Relative Sensors provide measurement to a fixed or variable measure-
ment. An example of a relative sensor would be a thermocouple, where
the temperature difference is measured, not the actual temperature.
4. Analog and Digital Sensors
◦ Analog Sensors produce continuous analog output signals, propor-
tional to its measurement. A few examples of analog sensors are: ac-
celerometers, pressure sensors, light, and sound sensors.
◦ Digital Sensors (also known as electronic or electrochemical sensors)
convert the data transmission, digitally. Examples include digital ac-
celerometers, pressure, and temperature sensors.
5. Miscellaneous Sensors
◦ Of course, there are plenty of other types of sensors in the field and
they would fall under the ‘other’ or miscellaneous category. These in-
clude electric, biological, chemical, radioactive and more.
5.Explain the static characteristics of sensor.
Static Characteristics of Sensors
Static characteristics of sensors describe the performance of a
transducer with very slow changes in the measurand. Static
characteristics include accuracy, linearity, precision, sensitiv-
ity…etc
Error
Accuracy of a sensor is usually specified by er-
ror. it tells you how closely the measured
value matches the true value.
Error is given by
teristics of Sensors.
NEED:-
• Sensors are omnipresent. They embedded in our bodies, automobiles, airplanes, cel-
lular telephones, radios, chemical plants, industrial plants and countless other appli-
cations.
• Sensors in industrial applications being used for process control, monitoring, and
safety, and in medicine being used for diagnostics, monitoring, critical care, and pub-
lic health.
• sensors for exploring space and improved environmental monitoring.
• Without the use of sensors, there would be no automation!
CHARACTERISTICS:-
Range : the difference between the maximum and minimum value of the sensed pa-
rameter
Resolution: The smallest change the sensor can differentiate.
Sensitivity: It is the ratio of change in output to a unit change of the input.
Error: Error is the difference between the result of the measurement and the true
value of the quantity being measured
Accuracy: It is the difference between measured value and true value
Precision: Precision is the ability to reproduce repeatedly with a given accuracy.
Repeatability: The ability of a sensor to give same output for repeated applications of
same input value.
Repeatability = (maximum – minimum values given) X 100 ⁄ full range.
Impedance: It is the ratio of voltage and current flow for sensor. For a resistive sensor,
the impedance Z is same as the
resistance R& its unit is ohms.
Response time: Response time is the amount of time required for a sensor to respond
completely to a change in input.
2. Explain the physical or chemical sensing principles of transduction.
,3. Explain with a neat diagram the components of measurement
system.
4.What is a Sensor? Briefly explain the classification of sensors.
SENSOR- A device that detects the changes in electrical or physical or other quantities
and thereby produces an output as an acknowledgement of change in the quantity is
called as a Sensor. Generally, this sensor output will be in the form of electrical or opti-
cal signal.
Classification of Sensors
Sensors can be ranked into various classification systems, but for the sake of sim-
plification, we have divided them into 5 core classifications.
1. Active and Passive Sensors
◦ Active Sensors (also known as parametric sensors) are sensors that
require an external power source to operate. Examples of active sen-
sors include GPS sensors and radar sensors.
◦ Passive Sensors (also called self-generated sensors) generate their
own electric signal and do not require any external power source. Ex-
amples of passive sensors include thermal sensors, electric field sens-
ing, and metal detecting.
2. Contact and Non-Contact Sensors
◦ Contact Sensors are those that require physical contact with their stim-
ulus. Familiar examples of contact sensors are temperature and strain
gauge sensors.
◦ Non-Contact Sensors, on the other hand, require no physical contact.
These types of sensors include optical and magnetic sensors, as well
as infrared thermometers.
, 3. Absolute and Relative Sensors
◦ Absolute Sensors mimic its name by providing an absolute reading of
its stimulus. For example, a thermistor always measures the exact, or
absolute, temperature reading.
◦ Relative Sensors provide measurement to a fixed or variable measure-
ment. An example of a relative sensor would be a thermocouple, where
the temperature difference is measured, not the actual temperature.
4. Analog and Digital Sensors
◦ Analog Sensors produce continuous analog output signals, propor-
tional to its measurement. A few examples of analog sensors are: ac-
celerometers, pressure sensors, light, and sound sensors.
◦ Digital Sensors (also known as electronic or electrochemical sensors)
convert the data transmission, digitally. Examples include digital ac-
celerometers, pressure, and temperature sensors.
5. Miscellaneous Sensors
◦ Of course, there are plenty of other types of sensors in the field and
they would fall under the ‘other’ or miscellaneous category. These in-
clude electric, biological, chemical, radioactive and more.
5.Explain the static characteristics of sensor.
Static Characteristics of Sensors
Static characteristics of sensors describe the performance of a
transducer with very slow changes in the measurand. Static
characteristics include accuracy, linearity, precision, sensitiv-
ity…etc
Error
Accuracy of a sensor is usually specified by er-
ror. it tells you how closely the measured
value matches the true value.
Error is given by
