What are Sensors and Its Types?

In this tutorial, we are going to learn about what are Sensors and Its Types?


It is a device that measures physical input from its environment and converts it into data that can be interpreted by either a human or machine.

What is the Need of Sensors?

  • For any system to interact with their environment, sensors and actuators are needed.
  • Atomization can’t be imagined without sensors.
  • These are used in automobiles, cellular telephones, airplanes, radios, industrial plants and many other applications.

Characteristic of Sensor

It is depending on the value of some parameters which are the below list:

  • Static Characteristic : The properties of the system after all transient effects have settled to their final or steady state.
  • Dynamic Characteristic : The properties of the system based on transient to an input.

Classification of Sensor

Based on the power source below are the details:

  1. Active Sensors It requires external excitation or a power signal, for example – a thermocouple.

2. Passive Sensors Passive Sensors which does not require any external power signal and directly generate output, for example – Thermistors.

Based on the mean of detection used in sensors

  • It can be electric, biological, chemical, radioactive etc.

Based on conversion phenomenon

  • These are photoelectric, thermoelectric, electromagnetic etc.

Based on output

  • Analog Sensors – Which produce continue output signal with respect to quantity being measured like temperature and light sensors.
  • Digital Sensors – These are work with discrete or digital data. Example – Digital Encoders, IR sensors.

Types of Sensor

TemperatureThermistors, Thermocouple
PressurePressure Gauge, Barometer
OpticalPhotodiodes, Phototransistors, IR sensors, CCD Sensors
Mechanical  Strain Gauge, Capacitive Diaphragms
Motion, VibrationAccelerometers, Mass airflow sensors
PositionGPS, Ultrasound based sensors
ElectromagneticHall Effect Sensor, Magnetometer
ChemicalpH Sensor, Infrared gas Sensor
RadiationIonization Detectors

Below is the list of Measurement of Signals:

ThermalTemperature, heat, heat flow, entropy, heat capacity etc.
RadiationGamma rays, X-rays, ultraviolet, visible and infrared light, microwaves, radio waves etc.
MechanicalDisplacement, velocity, acceleration, force, pressure, mass flow, acoustic wavelength and amplitude etc.
MagneticMagnetic field, flux, magnetic moment, magnetization, magnetic permeability etc.
Mechanical  Strain Gauge, Capacitive Diaphragms
ChemicalHumidity, pH level and ions, gas concentration, toxic and flammable materials, the concentration of vapours and odours, pollutants etc.
BiologicalSugar, proteins, hormones, and generate etc.

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