The document provides an overview of sensors, defining them as devices that detect and respond to environmental inputs like light and temperature. It outlines criteria for selecting sensors, such as accuracy and environmental conditions, and lists various types including temperature, pressure, and humidity sensors. Specific sensors sold by Nutronics India, like temperature, humidity, and pH sensors, are also described with explanations of their functions.

1. SENSORS AND ITS TYPES
By: Nutronics India1

2. WHAT ARE SENSORS?
 A sensor is a device that detects and
responds to some type of input from
the physical environment.
 The specific input could be light, heat,
motion, moisture, pressure, or any one
of a great number of other
environmental phenomena.
 The output is generally a signal that is
converted to human-readable display
at the sensor location or transmitted
electronically over a network for
reading or further processing.
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3. CRITERIA TO CHOOSE A SENSOR
 There are certain features which have to be considered when
we choose a sensor. They are as given below:
 Accuracy
 Environmental condition – usually has limits for temperature/
humidity
 Range – Measurement limit of sensor
 Calibration – Essential for most of the measuring devices as the
readings changes with time
 Resolution – Smallest increment detected by the sensor
 Cost
 Repeatability – The reading that varies is repeatedly measured
under the same environment 3

4. TYPES OF SENSORS
 Temperature – Thermistors, thermocouples, RTD’s, IC and many more.
 Pressure – Fibre optic, vacuum, elastic liquid based manometers, LVDT, electronic.
 Flow – Electromagnetic, differential pressure, positional displacement, thermal mass, etc.
 Level Sensors – Differential pressure, ultrasonic radio frequency, radar, thermal
displacement, etc.
 Proximity and displacement – LVDT, photoelectric, capacitive, magnetic, ultrasonic.
 Biosensors – Resonant mirror, electrochemical, surface Plasmon resonance, Light
addressable potentio-metric.
 Image – Charge coupled devices, CMOS
 Gas and chemical – Semiconductor, Infrared, Conductance, Electrochemical.
 Acceleration – Gyroscopes, Accelerometers.
 Others – Moisture, humidity sensor, Speed sensor, mass, Tilt sensor, force, viscosity.
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5. SENSORS SOLD BY NUTRONICS INDIA
 Temperature Sensors
 This device collects information about temperature from a
source and converts into a form that is understandable by
other device or person.
 The best illustration of a temperature sensor is mercury in
glass thermometer. The mercury in the glass expands and
contracts depending on the alterations in temperature.
 The outside temperature is the source element for the
temperature measurement. The position of the mercury is
observed by the viewer to measure the temperature.
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7.  Humidity Sensor
 A humidity sensor (or
hygrometer) senses,
measures and reports both
moisture and air
temperature.
 The ratio of moisture in the
air to the highest amount of
moisture at a particular air
temperature is called
relative humidity.
 Relative humidity becomes
an important factor, when
looking for comfort.
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8.  pH Sensors
 pH sensor basically works on the fact that interface of
two liquids produces a electric potential which can be
measured.
 In other words when a liquid inside an enclosure made
of glass is placed inside a solution other than that liquid,
there exists an electrochemical potential between the
two liquids.
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