Sensors can be categorized as either active or passive. Active sensors require an external power source to respond to environmental inputs and generate an output, such as sensors used in weather satellites. Passive sensors do not require external power and rely on environmental sources like light or heat, such as mercury thermometers. Sensors are used across many industries and applications, including in industrial equipment, healthcare devices like heart rate monitors, consumer electronics with light and proximity sensors, agriculture with soil and climate sensors, and security systems using cameras, door sensors, and biometrics.

1. UNDERSTANDING
OF SENSORS AND
THEIR TYPES

2. INTRODUCTION :-
A sensor is a device that detects and responds to
some type of input from the physical environment.
The input can be light, heat, motion, moisture,
pressure or any number of other environmental
phenomena. The output is generally a signal that is
converted to a human-readable display at the
sensor location or transmitted electronically over a
network for reading or further processing.
Examples :- LDR or Light Dependent Resistor

3. CATEGORITATION OF SENSOR :-
• Sensors can be categorized in multiple ways. One common approach
is to classify them as either active or passive.
An Active sensor is one that requires an external power source to be
able to respond to environmental input and generate output. For
example, sensors used in weather satellites often require some source
of energy to provide meteorological data about the Earth's
atmosphere.
A Passive sensor, on the other hand, doesn't require an external
power source to detect environmental input. It relies on the
environment itself for its power, using sources such as light or thermal
energy. A good example is the mercury-based glass thermometer. The
mercury expands and contracts in response to fluctuating
temperatures, causing the level to be higher or lower in the glass
tube. External markings provide a human-readable gauge for viewing
the temperature.

5.  Piezoelectric sensors
 Semiconductors sensors
 Pn-junctions
 Photodiodes
 Photon detectors
 Hall-effect sensor
 Vibration sensors
SOME MORE EXAMPLES OF SENSORS :
 Temperature sensor
 Light sensor
 Ultra sonic sensors
 pressure sensors
 IR sensor
 Biosensor
 Magnetic sensors

6. APPLICATION OF SENSOR :-
1) Sensor are used in many industrial and home appliances.
2) Sensor are used in health care by heart rate monitors,
blood glucose sensors and temperature sensor.
3) It is also used in consumer electronics by light sensor,
proximity sensors.
4) It is highly used in agriculture by using soil sensors,
temperature and humidity sensors and GPS and
geographic Information system.
5) we can used sensor in security system by using security
camera, door and window sensor and biometric sensors.

7. THANK YOU