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| '''Capacitive displacement sensors''' “are non-contact devices capable of high-resolution measurement of the position and/or change of position of any conductive target”.<ref name="LionCapOverview">[http://www.lionprecision.com/capacitive-sensors/index.html#apps Lion Precision Capacitive Sensor Overview], An overview of [[capacitive sensing]] [[technology]] from Lion Precision.</ref> They are also able to measure the thickness or density of [[Non-conductor|non-conductive]] materials.<ref name="SensorTechHandbook">{{cite book|isbn=0-7506-7729-5|title=Sensor Technology Handbook|page=94|url=http://books.google.com/books?id=fdeToUK8edMC&pg=PT94|author=Jon S. Wilson|publisher=Newnes|year=2005}}</ref> Capacitive displacement sensors are used in a wide variety of applications including [[semiconductor]] processing, assembly of precision equipment such as [[disk drive]]s, precision thickness measurements, [[machine tool]] [[metrology]] and [[assembly line]] testing. These types of sensors can be found in [[machining]] and [[manufacturing]] facilities around the world. | | Cooks everywhere will inform you that they can't carry out at their greatest with no their trusty chef's knives. Read the testimonials and then try to decide between this set or the Hugely Rated Analon Cutlery Set ! The picture under shows a Chicago Cutlery Fusion 18-Piece Knife Set we bought and utilised every day as it sat on our kitchen counter. The knives were very sharp and my wife Jerri reduce herself the 1st time she utilised the set and I reduce myself as I was getting fun cutting green peppers. My wife and I loved this set, but we have not too long ago sold it on this web site to test and evaluation one more set.<br><br>After a sale price tag and a promo code, I was capable to find a 14-piece set of Chicago Cutlery knives that retails for $129. In the event you loved this informative article and you wish to receive much more information relating to Greatest Bread Knife 2014 ([http://www.thebestkitchenknivesreviews.com/best-japanese-knives-chef-models-review/ Www.Thebestkitchenknivesreviews.Com]) kindly visit the web site. 99 at Macy's for $62. Whichever way you go, your kitchen really should have 3 common knives: a three"-4" Most effective Low-cost Bread Knife paring knife, an 8" Chef's knife and a 7"-ten" slicer for carving meats. If you happen to be petite, an 8" chef's knife could really feel too major select a 6" rather. Recognize a budget for your cutlery set.<br><br>When you acquire the steel collectively with the set, you can be sure that they are from a single and the same manufacturer and that the firmness of the honing steel conforms to the firmness of the blades of the knives from the set. If you are an experienced cook, you'll probably have a incredibly great idea of what knives and accessories your set ought to include. It is the desired way to mark high-quality in knife producing.<br><br>This affects every little thing about the knife like its flexibility, its ability to be rust-proof, its weight, and even its usage. Know what material the knife is produced from so that you are going to be confident what you will need from a knife. In the kitchen, this knife should really be in your hand 80-90% of the time. For initially time users, an 8 inch chef knife is advised and for a lot more knowledgeable customers the ten inch chef knife.<br><br>Not to mention, it tends to make a terrific groom's knife — guy's will also take pleasure in making use of this knife and favor it for its versatility, accuracy and rugged very good looks. This Ultimate Utility Knife attributes a distinctive low-frequency serration with a broad belly, enabling you to comfortably and gently rock the knife for full manage and precision. There are quite a few various knife firms from all over the world, but there are a handful of that stand out.<br><br>Knife sets are an location exactly where it really is worth spending as considerably as you can. Shopping for a set is the greatest way to go since cutlery is ordinarily a lot less expensive when purchased as a set. Not all knives are developed equally and you could potentially spend a lot of cash on a set that doesn't suit your desires. Answering these inquiries will determine irrespective of whether you have to have a uncomplicated knife set or a more substantial set.<br><br>MAC knives seem to be a single of the best kept secrets of the consumer kitchen knife market. But it's a big kitchen knife globe out there and everybody's welcome to their own opinion! I have a Cutco hand-me-down butcher's knife from my Mom which I like to use for slicing up unwieldy slabs of meat like sides of salmon or flank steak. But for standard, day-to-day use, I do not believe a Cutco chef's knife would hold up as well as the brands and models I've suggested in this post.<br><br>Knife sets are frequently filled with redundant blades, blades that are too short to get the job accomplished (like the serrated knives in the sets in the video), and so-known as "utility knives" for tasks which are practically usually superior served by a standard chef's knife. They are a superior knife set, but this high quality comes at a price point that can be difficult to swallow. In similar case it is the superior decision to make a decision for a Chef Knife Set. |
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| [[File:Pepperl+Fuchs capacitive sensor CJ8-18GM-E2-V1.jpg|thumb|Industrial capacitive sensor]]
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| ==Basic capacitive theory==
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| [[Capacitance]] is an electrical property which is created by applying an [[electrical charge]] to two conductive objects with a gap between them. A simple demonstration is two parallel conductive plates of the same profile with a gap between them and a charge applied to them. In this situation, the Capacitance can be expressed by the [[equation]]:
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| :<math> C = \dfrac{\varepsilon_0 K A}{d} </math> <ref name="Physics">{{cite book|isbn=0-87901-135-1|title=Physics Second Edition|author=Paul Allen Tipler|pages=653–660|publisher=Worth Publishers|year=1982}}</ref>
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| Where ''C'' is the capacitance, ε<sub>0</sub> is the [[permittivity of free space]] constant, ''K'' is the [[dielectric constant]] of the material in the gap, ''A'' is the area of the plates, and ''d'' is the distance between the plates.
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| There are two general types of capacitive displacement sensing systems. One type is used to measure thicknesses of conductive materials. The other type measures thicknesses of non conductive materials or the level a fluid.
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| A capacitive sensing system for conductive materials uses a model similar to the one described above, but in place of one of the conductive plates, is the [[sensor]], and in place of the other, is the conductive target to be measured. Since the area of the probe and target remain constant, and the [[dielectric]] of the material in the gap (usually air) also remains constant, "any change in capacitance is a result of a change in the distance between the probe and the target." <ref name="LionCapTheory">[http://www.lionprecision.com/tech-library/technotes/cap-0020-sensor-theory.html Capacitive Sensor Operation and Optimization How Capacitive Sensors Work and How to Use Them Effectively], An in depth discussion of capacitive sensor theory from Lion Precision.</ref> Therefore, the equation above can be simplified to:
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| :<math>C \propto \dfrac{1}{d} </math>
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| Where α indicates a proportional relationship.
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| Due to this proportional relationship, a capacitive sensing system is able to measure changes in capacitance and translate these changes into distance measurements.
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| The operation of the sensor for measuring thickness of non-conductive materials can be thought of as two capacitors in series, with each having a different dielectric (and dielectric constant). The sum of the thicknesses of the two dielectric materials remains constant but the thickness of each can vary. The thickness of the material to be measured displaces the other dielectric. The gap is often an air gap, (dielectric constant = 1) and the material has a higher dielectric. As the material gets thicker, the capacitance increases and is sensed by the system.
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| A sensor for measuring fluid levels works as two capacitors in parallel with constant total area. Again the difference in the dielectric constant of the fluid and the dielectric constant of air results in detectable changes in the capacitance between the conductive probes or plates.
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| ==Applications==
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| ===Precision positioning===
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| One of the more common applications of capacitive sensors is for precision positioning. Capacitive displacement sensors can be used to measure the position of objects down to the [[nanometer]] level. This type of precise positioning is used in the semiconductor industry where [[silicon wafer]]s need to be positioned for exposure. Capacitive sensors are also used to pre-focus the [[electron microscope]]s used in testing and examining the wafers.
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| ===Disc drive industry===
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| In the disc drive industry, capacitive displacement sensors are used to measure the runout (a measure of how much the axis of rotation deviates from an ideal fixed line) of disc drive [[Hard disk drive#Spindle|spindle]]s. By knowing the exact runout of these spindles, disc drive manufacturers are able to determine the maximum amount of data that can be placed onto the drives. Capacitive sensors are also used to ensure that disc drive platters are [[orthogonal]] to the spindle before data is written to them.
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| ===Precision thickness measurements===
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| Capacitive displacement sensors can be used to make very precise [[thickness]] measurements. Capacitive displacement sensors operate by measuring changes in position. If the position of a reference part of known thickness is measured, other parts can be subsequently measured and the differences in position can be used to determine the thickness of these parts.<ref name="LionCapThickness">[http://www.lionprecision.com/tech-library/appnotes/app-flash/f-cap-0030-thickness.html Capacitive Thickness Measurements], A tutorial on capacitive thickness measurements.</ref> In order for this to be effective using a single probe, the parts must be completely flat and measured on a perfectly flat surface. If the part to be measured has any [[curvature]] or [[deformity]], or simply does not rest firmly against the flat surface, the distance between the part to be measured and the surface it is placed upon will be erroneously included in the thickness measurement. This error can be eliminated by using two capacitive sensors to measure a single part. Capacitive sensors are placed on either side of the part to be measured. By measuring the parts from both sides, curvature and deformities are taken into account in the [[measurement]] and their effects are not included in the thickness readings.
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| The thickness of plastic materials can be measured with the material placed between two electrodes a set distance apart. These form a type of capacitor. The plastic when placed between the electrodes acts as a dielectric and displaces air (which has [[dielectric constant]] of 1, different than the plastic). Consequently the capacitance between the electrodes changes. The capacitance changes can then be measured and correlated with the material's thickness.<ref>[http://www.lionprecision.com/tech-library/appnotes/dual-0010-film-thick.html Film thickness gauge]</ref>
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| Capacitive sensors circuits can be constructed that are able to detect changes in capacitance on the order of a 10<sup>−5</sup> [[Farad|picofarads]] (10 attofarads).
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| ===Non-conductive targets===
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| While capacitive displacement sensors are most often used to sense changes in position of conductive targets, they can also be used to sense the thickness and/or density of non-conductive targets as well.<ref name="LionCapTheory"/> A non-conductive object placed in between the probe and conductive target will have a different dielectric constant than the air in the gap and will therefore change the Capacitance between probe and target. (See the first equation above) By analyzing this change in capacitance, the thickness and density of the non-conductor can be determined.
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| ===Machine tool metrology===
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| Capacitive displacement sensors are often used in metrology applications. In many cases, sensors are used “to measure shape errors in the part being produced. But they also can measure the errors arising in the equipment used to manufacture the part, a practice known as machine tool metrology”.<ref name="LLNL">[https://www.llnl.gov/str/Blaedel.html Lawrence Livermore National Laboratory: Engineering Precision into Laboratory Projects], Examples of advances made by LLNL in the field of precision measurement.</ref> In many cases, the sensors are used to analyze and optimize the rotation of spindles in various machine tools, examples include [[surface grinder]]s, [[lathe]]s, [[milling machine]]s, and [[air bearing]] spindles.<ref name="PrecisionSpindleMetrology">{{cite book|isbn=1-60595-003-3|title=Precision Spindle Metrology|author=Eric R. Marsh|publisher=Destech Pubns Inc|year=2009}}</ref> By measuring errors in the machines themselves, rather than simply measuring errors in the final products, problems can be dealt with and fixed earlier in the manufacturing process.
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| ===Assembly line testing===
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| Capacitive displacement sensors are often used in assembly line testing. Sometimes they are used to test assembled parts for [[uniformity]], thickness or other design features. At other times, they are used to simply look for the presence or absence of a certain component, such as [[glue]].<ref name="LionGlue">[http://www.lionprecision.com/tech-library/appnotes/app-flash/f-cap-0040-glue.html Sensing Glue on Paper], A tutorial on using capacitive sensors for glue sensing.</ref> Using capacitive sensors to test assembly line parts can help to prevent quality concerns further along in the production process.
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| ==Comparison to eddy current displacement sensors==
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| Capacitive displacement sensors share many similarities to [[eddy current]] (or inductive) displacement sensors; however capacitive sensors use an [[electric field]] as opposed to the [[magnetic field]] used by eddy current sensors <ref name="CapVEddy">[http://www.lionprecision.com/tech-library/technotes/tech-flash/cve/f-article-0011-cve.html Lion Precision Capacitive Eddy Current Comparison], A comparison between capacitive and eddy current sensing technology from Lion Precision.</ref><ref name="Siemens">[http://www.tech-pedia.com/Electrical_Engineering/Circuit%20Components/proximity%20sensors/capacitive/snrs_3.pdf Users Manual for Siemens Capacitive Sensors p.54]</ref> This leads to a variety of differences between the two sensing technologies, with the most notable differences being that capacitive sensors are generally capable of higher resolution measurements, and eddy current sensors work in dirty environments while capacitive sensors do not.<ref name="CapVEddy"/>
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| ==Other non-displacement capacitive sensing applications==
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| * Testing the moisture content of grain
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| * Soil moisture
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| * Humidity
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| * Detecting water content in fuels
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| * Fuel composition sensors (for [[flex fuel]] vehicles)
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| * Capacitive [[load cell]]s
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| ==See also==
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| *[[Proximity sensor]]
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| *[[Capacitive sensing]]
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| *[[List of sensors]]
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| *[[Inductive sensor]]
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| ==References==
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| <!--- See [[Wikipedia:Footnotes]] on how to create references using <ref></ref> tags which will then appear here automatically -->
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| {{Reflist|2}}
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| ==External links==
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| *[http://www.tectrends.com/cgi/showan?an=00174300 Medical Engineering ] - Patient Monitoring Using Capacitive Sensors
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| *[http://www.capacitance-sensors.com/capacitive_sensor_tutorial.htm Capacitive Sensors for Motion Control] - Tutorial on Capacitive Sensors for Nanopositioning Applications
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| *[http://www.lionprecision.com/tech-library/technotes/cap-0020-sensor-theory.html Capacitive Sensor Theory] - How Capacitive Sensors Work and How to Use Them Effectively
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| {{DEFAULTSORT:Capacitive Displacement Sensor}}
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| [[Category:Sensors]]
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| [[Category:Measuring instruments]]
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| [[fr:Capteur de déplacement capacitif]]
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| [[ru:Ёмкостный датчик]]
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Cooks everywhere will inform you that they can't carry out at their greatest with no their trusty chef's knives. Read the testimonials and then try to decide between this set or the Hugely Rated Analon Cutlery Set ! The picture under shows a Chicago Cutlery Fusion 18-Piece Knife Set we bought and utilised every day as it sat on our kitchen counter. The knives were very sharp and my wife Jerri reduce herself the 1st time she utilised the set and I reduce myself as I was getting fun cutting green peppers. My wife and I loved this set, but we have not too long ago sold it on this web site to test and evaluation one more set.
After a sale price tag and a promo code, I was capable to find a 14-piece set of Chicago Cutlery knives that retails for $129. In the event you loved this informative article and you wish to receive much more information relating to Greatest Bread Knife 2014 (Www.Thebestkitchenknivesreviews.Com) kindly visit the web site. 99 at Macy's for $62. Whichever way you go, your kitchen really should have 3 common knives: a three"-4" Most effective Low-cost Bread Knife paring knife, an 8" Chef's knife and a 7"-ten" slicer for carving meats. If you happen to be petite, an 8" chef's knife could really feel too major select a 6" rather. Recognize a budget for your cutlery set.
When you acquire the steel collectively with the set, you can be sure that they are from a single and the same manufacturer and that the firmness of the honing steel conforms to the firmness of the blades of the knives from the set. If you are an experienced cook, you'll probably have a incredibly great idea of what knives and accessories your set ought to include. It is the desired way to mark high-quality in knife producing.
This affects every little thing about the knife like its flexibility, its ability to be rust-proof, its weight, and even its usage. Know what material the knife is produced from so that you are going to be confident what you will need from a knife. In the kitchen, this knife should really be in your hand 80-90% of the time. For initially time users, an 8 inch chef knife is advised and for a lot more knowledgeable customers the ten inch chef knife.
Not to mention, it tends to make a terrific groom's knife — guy's will also take pleasure in making use of this knife and favor it for its versatility, accuracy and rugged very good looks. This Ultimate Utility Knife attributes a distinctive low-frequency serration with a broad belly, enabling you to comfortably and gently rock the knife for full manage and precision. There are quite a few various knife firms from all over the world, but there are a handful of that stand out.
Knife sets are an location exactly where it really is worth spending as considerably as you can. Shopping for a set is the greatest way to go since cutlery is ordinarily a lot less expensive when purchased as a set. Not all knives are developed equally and you could potentially spend a lot of cash on a set that doesn't suit your desires. Answering these inquiries will determine irrespective of whether you have to have a uncomplicated knife set or a more substantial set.
MAC knives seem to be a single of the best kept secrets of the consumer kitchen knife market. But it's a big kitchen knife globe out there and everybody's welcome to their own opinion! I have a Cutco hand-me-down butcher's knife from my Mom which I like to use for slicing up unwieldy slabs of meat like sides of salmon or flank steak. But for standard, day-to-day use, I do not believe a Cutco chef's knife would hold up as well as the brands and models I've suggested in this post.
Knife sets are frequently filled with redundant blades, blades that are too short to get the job accomplished (like the serrated knives in the sets in the video), and so-known as "utility knives" for tasks which are practically usually superior served by a standard chef's knife. They are a superior knife set, but this high quality comes at a price point that can be difficult to swallow. In similar case it is the superior decision to make a decision for a Chef Knife Set.