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, humidity, pressure, or any of many 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. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Some examples of the different types of sensors: In a mercury-based glass thermometer, the input is temperature. The contained liquid expands and contracts in response, causing the level to be higher or lower on the marked, human-readable indicator. An oxygen sensor in a car's emissions control system detects the gasoline/oxygen ratio, usually through a chemical reaction that generates a voltage. A computer in the engine reads the voltage and, if the mixture is not optimal, readjusts the balance. Motion sensors in various systems including home security lights, automatic doors, and bathroom fixtures typically send out some type of energy, such as microwaves, ultrasonic waves, or light beams, and detects when the flow of energy is interrupted by something entering its path . A photosensor detects the presence of visible light, infrared (IR) transmission, and/or ultraviolet (UV) energy. Water Sensor Principles of Operation Pipeline leak detection is used to determine if and in some cases where a leak has occurred in systems containing liquids and gases. Detection methods include hydrostatic testing, infrared and laser technology after pipeline erection and leak detection during service. Pipeline networks are the cheapest and safest mode of transportation for oil, gas and other fluid products. As a means of long-distance transportation, oil pipelines must meet high requirements for safety, reliability and efficiency. If maintained properly, pipelines can last indefinitely without leaks. The most significant losses that occur are caused by damage from nearby excavations. If a pipe is not maintained properly, it can corrode, particularly at construction joints, low spots where moisture collects, or places with imperfections in the pipe. However, these defects can be identified using inspection tools and corrected before they turn into a leak. Other reasons for losses include accidents, ground movements or sabotage. Water Sensor Applications Water sensors find applications in nuclear power plants, automobiles to measure the amount of gasoline left in the fuel tank, engine oil, cooling water, and brake/power steering fluid. . Industrial applications of water level sensors include water level sensing in transportation and storage tanks and water treatment tanks. Please note: this is just an example. Get a custom paper from our expert writers now. Get Custom Essay Produce different types of level instruments for their uses in municipal areas and also in the food and beverage industry.