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Sensor Systems According to IEEE (1999), 'sensor' means a ' component providing a useful output in response to a physical, chemical, or biological phenomenon ’. This component may already have some signal conditioning   (involves operations such as amplification, compensation, filtering, and normalization) associated with it.  Revised by IEEE, in 2003, the term `sensor' means ' a transducer that converts a physical, biological, or chemical parameter into an electrical signal ’.  According to Vocabulaire International de Metrologie (VIM), a transducer is a device used in measurement, ' that provides an output quantity having a specific relation to the input quantity '. The same document defines a sensor as the element of a measuring system ' that is directly affected by a phenomenon, body, or substance carrying a quantity to be measured '. In practice, the term 'sensor' is applied for designating:  one sensitive element;  a primary measuring t...

An ultrasonic sensor is an electronic device that measures the distance of a target object by emitting ultrasonic sound waves and converts the reflected waves into an electrical signal.  Ultrasonic waves travel faster than the speed of audible sound (i.e. the sound that humans can hear). The speed of the ultrasonic waves is approximately 343 meters/second. Ultrasonic sensors have two main components: the transmitter (which emits the sound using piezoelectric crystals) and the receiver (which encounters the sound after it has traveled to and from the target). Ultrasonic sensors are widely used in:  Ultrasonic sensors can be deployed for Distance measurement Proximity sensing Flow measurement Level measurement Distance measurement using ultrasonic sensor: In order to calculate the distance between the sensor and the object, the sensor measures the time it takes between the emission of the sound by the transmitter to its contact with the receiver.  The formula for this calcu...

Optical temperature sensors are temperature sensors that are based on optical technology – in most cases, on fiber optics. There are alternative techniques, in particular electronic temperature sensing. However, optical temperature sensors can offer important advantages such as:  High-voltage isolation Electromagnetic  and radiation immune Inherently intrinsically safe/ Intrinsically non-explosive Insensitive to lightning strikes Cryogenic and high temperature tolerant Simple, safe handling of the optical cable High resistance to dynamic fatigue Subsequent repair and mounting Perfect load transfer No corrosion or drift Installation of numerous sensors on the same line Fiber Optics Temperature Measurement System: Figure 1: Components of a typical optical temperature measurement system The general structure of an optical fiber temperature measurement system is shown in the above figure 1 which consists mainly of four components that are  the source,  fiber optic,...

Gas detectors  can be used to  detect  combustible, flammable, and toxic  gases  and oxygen depletion.  Modern society frequently encounters the use of both toxic and flammable gases on a daily basis. Gases are utilized in a controlled manner in a wide range of applications however it is essential that we employ critical safety systems to ensure we regulate and control the potential risks associated with an uncontrolled gas leak. Four basic types of gas sensors are widely used for gas detection and monitoring in commercial or industries: Catalytic gas sensors: The catalytic-type gas sensor consists of two elements:  A detector element (D):   which contains catalytic material and is sensitive to combustible gases, and  A compensator element (C): which is inert .  Combustible gases will  burn only on the detector element, causing a rise in its temperature and,  as a consequence, a rise in its resistance. Combustible gases will n...