 Hello, I am Milka Jagle, working as assistant professor in Department of Mechanical Engineering, Walshchand Institute of Technology, Solapor. Today we are going to learn about sensors, learning outcome. At the end of this session, learners will be able to identify various types of sensors. So these are the content for today's presentation. Sensors, selection criteria of sensors, force sensors, light sensors, proximity sensors, angular and linear position sensors, optical sensors and their applications. First, let us define what is sensor. According to Instrument Society of America, sensors can be defined as a device which provides a suitable output in response to the specified measurement or it can also be defined as element which subjected to physical change experiences a relative change or when the input is physical quantity and output is electrical then it is called as sensor. The block shows the physical parameter is converted into electrical output then that is known as a sensor. So sensors can be selected for various applications, there are various categories on which they can be chosen, first the accuracy, second environmental condition usually it has a limits for temperature and humidity. The range that is measurement limit of sensor, calibration is one of the important aspect in the sensors that is essential for most of the measuring devices, essential for most of the measuring devices as the readings change with time. Now I want you to pause the video for few seconds and list down the sensors which you come across in your day to day life. So what are various types of sensors which are used to measure temperature, which are used to measure flow, velocity, humidity and the other factors. So let us see the first type of sensor that is light sensor. The light sensor is a passive device that converts the light energy whether visible or in the infrared parts of the spectrum into electrical signal output. Light sensors are commonly known as photoelectric devices or photosensors because they convert light energy into electricity. Sensor is composed of photo conductor such as photo resistor, photo diode or photo transistor. Light sensors are used in cameras, infrared detectors. Light sensors are used in cameras, infrared detectors and ambient lightning appliances. So the figure one and two shows the light sensors which are used for various applications. The next sensor is a force sensor. The name itself indicates the sensor which used to measure the force can be known as a force sensor. Force sensor use load cells to weigh objects and prevent machinery from overloading. Force sensors are load cells, transducers that convert force into measurable electrical outputs. The force sensors are majorly electronic equipments whose material can be force sensing resistor. Generally the working principle of force sensor is that they respond to the applied load and weight and then transform them into quantifiable output. Figure three and four shows the load cells and the force cells. Figure three shows load cell sensor and figure four shows the force sensors. The next is proximity sensor. A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact or point of contact. A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation and looks for change in the field or return signal. A proximity sensor emits an electromagnetic or electrostatic field or a beam of electro radiation and waits for the return signals in the field. The object which is being sensed is known as a proximity sensor target. The object which is being sensed is known as proximity sensors target. The different types of proximity sensors are inductive proximity sensors, capacitive proximity sensors, ultrasonic proximity sensors, photoelectric sensors and hall effects sensors and etc. Figure five and figure six shows inductive proximity sensors and capacitive proximity sensors. The next type of sensors are angular and linear position sensors. The angular and linear position sensors are electronic devices used to simultaneously measure both angular and linear position changes relative to a reference position. The most common technologies used are hall effect, inductive, magneto-resistive and resistance. The figure number seven and figure number eight. Figure number seven and figure number eight shows linear and angular position sensors. The next type of sensors are optical sensors. An optical sensor converts light rays into an electronic signal. The purpose of optical sensor is to measure a physical quantity of light and depending on the type of sensor then translates it into the form that is readable by an integrated measuring device. Figure number nine shows the optical sensor. The next sensor is a microsensor, a very small sensor with physical dimensions in the submicrometer to millimeter range. A sensor is a device that converts a non-electrical physical or chemical quantity such as pressure, acceleration, temperature or gas concentration into electrical signal. Figure number ten shows a microsensor. These are the applications in various fields. The first is shock detection, machine monitoring applications, vehicle dynamics, low power applications, structural dynamics, medical aerospace, nuclear instrumentation and in mobile touch keypads, lamps which brighten or dim on touching its base and touch sensitive buttons in elevators. These are few applications which I have jotted here but there are n number of applications in the real time applications. These are the references, book W Bolton, second is Shetty and Coke and the third book is Mahalik.