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A measurand is a subject to measuring physical size, for example: acceleration, moving, force, expense, level, position, pressure, mechanical tension, temperature, speed etc. It can on occasion measureable be electric size, such, as a current, tension or frequency, which will be transformed in an electric signal, suitable for the use in other parts of the system. Thus a measuring transformer is an electric transducers element.
An entrance transducer, transforming, sensors a measurand in an electric signal, - it a device, suitable for the use in other parts of the system. True, although entrance transducers generate ...
Semiconductor devices belong to categories of electronic components which are named semiconductors. Clean or unalloyed semiconductor usually not used in these devices, but originally alloyed by admixtures in a semiconductor crystalline grate they become ...
In the wide range of temperatures dependence of resistance of semiconductor on the temperature of R(T) difficult character has and depends on the type of alloying admixture and alloying level. It is therefore impossible to express dependence of R(T) a simple formula which would allow to execute calibrating ...
The Hall effect and the physical basis of the Hall sensor. If along a standard to skip the electric current of I, and athwart to create the magnetic field of B the plane of plate, then on the lateral planes ...
Quality of strain gauge is determined by their coefficients of strain sensetivity K and in size temperature coefficient of resistance (TCR) - ΔR/RΔÒ. What higher coefficient of tensosensitivity To and less than temperature coefficient of resistance (TCR) of material which strain gauge is made from, the higher his quality.
For example, for wire strain gauge, made from the alloys ...
Photo-electric are such primary measuring transducers, which react on an electromagnetic radiation, falling on the surface of transforming element. A radiation can be visible, and also to have a large or less ...
Solar elements are photo-electric transducers which convert the radiated electromagnetic energy into electric, i.e. the change of measureable value of radiation will be transformed in the change of output tension.
The construction of transducer plugs in itself the layer of photo sensible of high-resistance material ...
Examined the device, the operating principle and method for measuring the deformation of an object using metal foil strain gages and semiconductor strain gauges. The example of the measurement.
This gauge is a device electrical resistance of which changes when it is deformed. This change in resistance due to the magnitude of the mechanical deformation via ε gauge ...
There are two types of semiconductor radiation sources: sources of incoherent radiation - LEDs and sources of coherent radiation - lasers. Greatest practical widespread radiation sources based on p- n junction.
Emission occurs due to recombination of injected carriers in a part of p -n- junction ( or a part of the p - n- region adjacent to the interface of p -n- junction). Recombination occurs at the transition from the upper carriers to lower levels, while transitions can be of two types - direct (no change of momentum ) and indirect (with a change of momentum). Interband transitions between the conduction band minimum and valence band maximum radiation accompanied by effective if direct transitions, ie, the minimum and maximum are located at the same value of the wave vector k. Such transitions occur, for example, in gallium arsenide for k = 0.
In semiconductors with indirect transitions probability of interband transitions is negligible. Nevertheless, radiative ...
The description of the experimental semiconductor transducers (sensors) temperature, deformation of the magnetic field.
Semiconductor materials are highly sensitive to various external influences and the development based on these transducers (sensors) physical quantities...
Thermocouple of precious metal wire lengthening made more often from the same materials as the main thermoelectrodes. Thermocouple of precious metal extension wire made of other (not expensive) materials, developing in tandem with each other in the temperature range 0 - 150 ° C, the same thermal emf as thermocouple electrodes. For example, platinum thermocouple - Platinum thermoelectrodes extension made of special copper alloy, which form a thermocouple, which is identical in the thermo emf thermocouple platinum - Platinum in the range 0 - 150 °C. Thermocouple Chromel - Alumel thermoelectrodes extension made of copper and constantan, and chromel thermocouple - Copel extension can be a major thermoelectrodes made in the form of flexible wires. If the wrong extension thermoelectrodes connect, then you might experience increased accuracy ...
Calibration charts are shown for different thermocouples, which can be used for temperature measurement with thermocouples of known alloys. For a condition, when a free end(shut) of thermocouple is at the zero of degrees celsius. Chromel-alumel et al. ...
The process to make a thermocouple is to create a firm joint (welding, Fig. 3) of two materials (wires). To this effect, you may use a power source of sufficient capacity (for example, LACT - laboratory autoconnected transformer, car battery). Connect a thermocouple (both free ends) with wires 1, being previously mechanicall y connected, to one pole of power source(Fig. 1), and a contact, being connected with a piece of graphite (for example, pencil 2) - to the second pole.
The electrical arc arises and the wires of thermocouple are welded if you touch the graphite with connected ends of thermocouple. The voltage, necessary for welding, is selected on experimental basis starting from not large voltages of 3-5 V. The optimal ...
Of semiconductor thermistors most widely adopted germanium thermistors. They have good long-term stability, high sensitivity (≅ 100% / K at 4.2 K) can ensure the accuracy of the order of 0.01 K. Produces germanium resistance thermometers of the bulk germanium, dispersed (sensorse.com/page29en.html), germanium films on insulating substrates. There are germanium thermistors, which are due to the low value of the magnetoresistance in magnetic fields up to 6 T to ensure accuracy of 0.01 K.
Addition of germanium to make use of cryogenic thermistors and other semiconductor materials such as gallium arsenide. However, it is considered that the metrological characteristics of these thermometers are generally worse than germanium.
There are also carbon sensors ...
To comparatively recent time the effect of Hall was used only for the study of electric properties of matters. With opening of elementary semiconductors and semiconductor connections, such, as, for example, Gå, ÍgSå, InSb, ÍgÒå, InÀs, possessing large by mobility of transmitters current - electrons or holes, this effect found the row of essential applications for the row of devices.
The staple of any the so-called sensor of hall - effect (Hall) serves as of these devices. He is a small on a size semiconductor plate of rectangular form with soldered to her by four wire electrodes from which two current, and two halls. This type of sensor got the name of crystalline. There are also pellicle sensors. On a thin isolating plate, for example mica, the skim of semiconductor matter is laid on, usually by the method of evaporation in a vacuum. Similarly as well as in the previous case, wire conclusions contact with a semiconductor.
There are the first types of crystalline and pellicle sensors in Soviet Union, and also some devices on their basis were worked out in Institute of semiconductors ...
Along with the advantages of semiconductor strain gauges are also some disadvantages that prevent the use of such sensors.
Application of semiconductor strain gauges is very perspective in acselerometer. Modern semiconductor strain gauges (sensors) on a construction and technical descriptions differ from described below. But principle of work and basic parameters differ small. ...
The high carrier mobility in GaAs, and thus the high magnetic sensitivity is used to create the Hall sensor.
Technical characteristics of magnetic field sensors based on Hall effect (Hall sensors) depend on the material used and the geometric size and shape of the sensitive ...
Thus, the sensors of magnetic-field are capable of working in the wide range of temperatures, possess weak temperature dependence of sensitiveness and initial output signal (less than 0.1%). Non-linearity of output signal does not exceed 0.1% in the field to 2Òë, a sensitiveness can arrive at 500 ìÂ/Òë.
The researches conducted by us showed that at 300Ê the worked out sensors are capable of working to the levels of neutron irradiation a 10^15 cm - 2. The nascent changes of descriptions of transducers to the levels of 1õ10^16 ñì- 2 can be up to a point taken into account, due to that good repetition of results was. Transducers can be used both for diagnostics of technical devices of atomic energy, êðèîãåííîé technique and, due to a high sensitiveness, in ecology for control of parameters of environment, such as the electromagnetic fields of and other ...
Currently, Hall sensors are widely used in the automotive industry. They are used to control displacements and rotations of various parts of the vehicle, vibrations of the engine, the ignition ...
How to check the Hall sensor? There are several ways to check the health of the automotive Hall sensor. One of the most simple is the following. Connected automotive Hall sensor according to the diagram, as shown in Fig.2. Removed the Hall sensor food can be submitted from the Krone battery (9 V). To measure the output signal (voltage) V best used compact digital multimeter. If you change the magnetic flux through the sensing element of a Hall sensor (for example, the rotation of the rotor shaft or just the overlap of the metal plate of the gap) will change ...
Hygrometer with a conductive film consists of a sensor - layer hygroscopic substance deposited on an insulating substrate. As a hygroscopic substance (hygrometer sensor) often use certain metal oxides, and other materials. Electrical contacts are made, usually in the form of a comb. With increasing gas humidity and therefore sensitive film its electrical resistance decreases. Dependence in most cases is exponential.
Hygrometer with a conductive film has a fairly short response and is often used to determine the moisture content of small values of air (gas).
Depending on the humidity of the air (gas) in hygrometers with a conductive film changes the electrical resistance of the film - the sensor hygrometer.
This type of hygrometer measures the relative humidity of the air, which...
The accelerometer is a transducer that measures the acceleration of the object, which he acquired at the displacement relative to its initial position. Accelerometers are used to measure acceleration in the horizontal displacements caused by the acceleration of gravity. Currently mass produced accelerometers based on micro electromechanical systems (MEMS)....
Solders are special alloys used in brazing. Soldering is carried out or with the aim of creating mechanically strong (sometimes sealed) seam, or with the aim of obtaining a constant (not burst or moving) electrical contact with small transfer resistance. When soldering the joints and solder are heated. Since the solder has a melting point much lower than the metals to be joined, then it melts, while the solder metals remain solid. On the border between the molten solder and the solid metal there are complex physical ...
Dependence E.M.F. thermocouple : chromel - kopel from a temperature for a condition, when a free end (shut) of thermocouple is at the zero of degrees celsius. Chromel - Copel thermocouple (TCC, Type L) have the highest differential sensitivity ...
In the simplest case, the ionization chamber is a device of two metal plates, insulated from one another and separated by a gas gap. Any air condenser can act as ionization chambers. The space between the plates is called the working volume of the chamber. If the plate to apply a constant voltage, the space is formed between the electric field whose lines of force are directed from the positive plate to the negative. On electrically...
The company's engineers Ie has developed a wireless charger that charges batteries of various mobile devices from it at the distance of nine metres. A charging station was named Cota. The manufacturer intends to put ...
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May 22-25, 2016 - Washington, D.C.
The world's largest nanotechnology event, Nanotech 2016, delivers application-focused research from the top international academic, government and ...
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This 4th edition of PHOTOPTICS will feature 3 different tracks on Optics, Photonics and Lasers. Researchers, engineers and practitioners interested in any of these fields are welcome ...
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The project plans to hold a new SWorld annual international scientific and practical conference "Intellectual potential of the XXI century" 2015 ". Time: 10 to 22 November 2015
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Annual Conference and Exhibition
May 20-21, 2015
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- How to hide from the thermal imager
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In Japan optical disks of memory which can keep information of 300 million years ...
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The deadline for paper submission is for September 30, 2014.
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" CURRENT ISSUES modern technology "
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Date For Abstract Submission: 27th February,2014.
Final Paper Submissions: 20th March, 2014
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September 08-10, 2014 at Philadelphia, USA
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International Conference "Actual problems of modern technology"
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(Force meters, strain gauge dynamometers)
Transducers of force, pressure. The shape and design of beams and elastic elements, the calculation formulas. Stability.
Tensoresistance force transducers and pressure are the most diverse applications, since they have a very compact design can measure force and pressure in the range >>>
Modern automobiles equipped with fuel injection systems that increases engine power, efficiency. The use of such systems necessitates the use of various sensors to automate driving.
Here is a brief overview of the concepts and purpose of the basic sensors in modern fuel injected automobiles...
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SENSORS OF PHYSICAL PARAMETERS
