Basic Knowledge of SMT Frequently Used Electronic Components SMT common electronic components basic knowledge 1. The classification of common electronic components.    (1), Resistors (Res): Electronics symbol R                           Chip resistors, color ring resistors,                           Voltage-sensitive resistors, temperature-sensitive resistors    (2), capacitors (Cap): electronics symbol C                           Chip Capacitor, ** Capacitor, Electrolytic Capacitor                           Magnetic chip capacitors, polyester capacitors, tantalum capacitors     (3), inductors (IND): electronics symbol L                           Chip laminated inductors, chip wirewound inductors                           Color ring inductors, wirewound inductors     (4), diode (DIO): electronics symbol D                           Chip diode, silicon diode,                           Germanium diode, light-emitting diode     (5), triode (TRA): electronics symbols Q§T     (6), switch (KEY): electronics symbol SW                           Toggle switch, key switch     (7), integrated circuits (IC): electronics symbol U                            QFP, PLCC, SOP, BGA     (8), crystal (CRYSTAL): electronics symbol Y     (9), socket (JACK): electronics symbol J     (10), Optocoupler (OPTO)     (11), transformer     (12), FUSE (fuse) 2. Commonly used electronic component units and conversion.    (1), resistance.           Basic unit: Ohm Symbol: Ω           Common unit: kilo-ohm Symbol: KΩ                               Megaohm Symbol: MΩ           Conversion relationship: 1MΩ = 1000KΩ = 1000000Ω     (2), capacitance.             Basic unit: Farad Symbol: F             Common unit: millifar Symbol: mF                        Microfar Symbol: μF                        Nanofar Symbol: nF                        Pico-farad Symbol: pF             Conversion relation.             1F=103mF=106μF=109nF=1012pF      (3) Inductance.               Basic unit: Henry Symbol: H               Common unit: millihenry Symbol: mH                        Microhenry Symbol: uH                        Nano-Henry Symbol: nH               Conversion relation.               1H=103mH=106μH=109nH 3:Common electronic component error and voltage indication method      (1), error letter identification method.             C D J K M Z           ±0.25pF ±0.5pF ±5% ±10% ±20% +80% -20      (2), Pressure-resistant letter identification method.             A B C                               25V 50V 100V SMT often electronic components basic knowledge is introduced here!

SMT component specification identification and related knowledge SMD component specifications identification 1: usually combined with the length and width of the chip components, said the chip components    Volume size of a representation, usually in inches (Inch) (1Inch = 2.54cm) 2: commonly used SMD component specifications are as follows.  A: 0402 that the component: length 0.04Inch width 0.02Inch B:0603 that the component: length 0.06Inch width 0.03Inch   C:0805 means the component: length 0.08Inch width 0.05Inch  D:1206 means the component: length 0.12Inch width 0.06Inch E:1210 means the component: length 0.12Inch width 0.1Inch Judge the correctness of smt material standards  1:The code on the material tray must correspond to the code on the customer's list.  2:The model number of the material must correspond to the model requirement on the customer's list.  3:The specification of the material must correspond to the requirement on the customer's list.  4: The tolerance of the material must correspond to the requirements on the customer's list.  5: The silkscreen on the material object is consistent with the requirements of the customer list, if not consistent then                   There must be valid customer documents to support.  6: There are special requirements to see the manufacturer of the material, the material manufacturer must meet the customer's requirements SMT material packaging  1: SMD components are usually packaged in plastic disks in the shape of a garden tray  2: IC material packaging   IC components are usually packaged in TRAY trays, TRAY specifications are usually based on TRAY trays can be loaded IC (width and length) number to indicate. SMT component specification identification and related knowledge is introduced.

What are eBooks E-books are now becoming a hot product.   What is an e-book?  At present, the domestic academic community as well as the community initially identified e-books as: "e-books represent digital publications read by people, thus distinguishing them from traditional publications with paper as the carrier, e-books are the use of computer technology will be a certain amount of text, pictures, sound, images, and other information, recorded in a digital way in the optical, electrical, magnetic as the medium of the device with the help of a specific equipment to read, copy, and transmit." 　E-books are composed of three elements  1E-book's content, which is mainly a book produced in a special format that can be distributed over a wired or wireless network, usually organized by a specialized website.   2 E-book readers, which include desktop personal computers, personal handheld digital devices IPAD, specialized electronic devices, such as "Hanlin e-book".  3 e-book reading software, such as ADOBE's AcrobatReader, Glassbook's Glassbook, Microsoft's MicrosoftReader, Superstar's SReader and so on. As you can see, both the content of e-books, reading devices, or e-book reading software, and even web publishing are all titled as e-books.   The main formats of e-books are PDF, EXE, CHM, UMD, PDG, JAR, PDB, TXT, BRM and so on, and at present, many popular mobile devices are supported by their reading formats. The common e-book formats for mobile terminals are UMD, JAR, TXT. E-books portable, easy to use, high-capacity features are very suitable for modern life, digital copyright trade and the development of Internet technology, so that users of e-books can conveniently buy more books at a lower price, laying the foundation for the popularity of e-books. 　According to the U.S. Consumer Electronics Association data, the e-reader market last year, revenue growth of 265%, is one of the fastest growing * products. U.S. Amazon.com issued a statement on January 26, 2010, said the 25th Christmas Day, Amazon.com's e-book sales ** more than paper books, its e-book reader Kindle has also become the site's history of the most sold gift goodies.  In addition, Japan and South Korea's Sony, Samsung, China's Han Wang, Founder, Datang Mobile have entered the e-book market. But the hot e-book market is still internal and external problems, and there are many variables in its future.  Although the current e-book market is fired, but still facing internal and external problems. In the long run, e-books may only be a flash in the pan, flocking to e-book manufacturing enterprises will encounter a serious crisis.

SMT chip part of the component interpretation Diode    A, from the package material can be divided into glass diodes, plastic diodes;    B. From the semiconductor material: can be divided into germanium material diode, silicon material diode.        From the function points: switching diodes, rectifier diodes, light-emitting diodes.    C. The characteristics of different semiconductor materials are different.         Germanium diodes, rectifier diodes, light-emitting diodes are mostly silicon diodes.        tube, general germanium diode using glass package, silicon diode using plastic.    D, diodes have polarity distinction, the negative pole of the general diode with white, red or black ** ring marking.       The negative terminal of a diode is marked with a white, red or black ring, and light-emitting diodes generally use different pin lengths to distinguish polarity.       Light-emitting diodes generally use different lengths of the pins to distinguish polarity, the shorter pins for the negative pole    Triode Triode classification according to the triode process can be divided into NPN tube, PNP tube, MOS tube. Integrated Circuit (IC) IC classification is mainly based on the IC package form, can be basically divided into: SOJ (double-row inner J-shaped), PLCC (quadrilateral J-shaped pins), QFP (quadrilateral) BGA (the bottom of the ball-shaped form) three forms.    A, SOJ package IC (double-row in-line J-shaped inside)          SOJ IC (double-row in-line), IC screen printing surface with the model number screen printing, the direction of the instruction notch, the first foot instruction mark.    B, PLCC (quadrilateral J-shaped pin)      Internationally adopted IC foot position of the unified standard: the direction of the IC notch towards the left, close to their own side of the pin from left to right for the first foot to the Nth foot, away from their own side from right to left for the N + 1 foot to the last foot. Note: Some manufacturers produce ICs that are not marked with a notch to indicate the direction, but with a silkscreen to indicate the direction of the identification of the pin position and the same method as described above.    C. QFP (Quadrilateral Finned Pin)       QFPIC package: In the integrated circuit of the amount of integration and the increase in functionality at the same time, IC pins continue to increase, while the volume of the IC can not be increased too much, so the IC to solve this contradiction in the design of the four sides of the pins have a positive quadrilateral IC package form.     Positive quadrilateral IC pin pin identification method: the direction of the indicator mark towards the left and close to their own, facing their own row of pins on the left side of the first pin for the first IC foot, according to the counterclockwise direction in turn for the second foot to the Nth foot.    D. BGA (Bottom Gland Assembly)      BGA package: With the technological update of the integration of integrated circuits continue to improve, powerful IC continues to be designed, the pin continues to increase the QFP way can not solve the demand, so the BGA package was designed to take full advantage of the IC and PCB contact area, significant use of the IC's bottom and vertical soldering method, thus solving the problem of the pin! Crystal Vibrator   A crystal oscillator is an electronic component that generates a fixed frequency through a certain voltage excitation, and is widely used in home appliances, instruments and computers.   There are two types of crystals: passive crystals and active crystals. Passive crystal oscillator is generally only two pins, active crystal oscillator is generally four pins, and in the insertion of the corresponding feet have strict requirements, if inserted in the opposite direction will be crystal damage. (At the same time, the chip crystal vibration membrane is very thin, pick up when you want to take lightly put). Optocoupler identification   Mainly: SMD optocoupler, hand-inserted optocoupler. The difference between IC and IC is that IC generally have 8 or more than 8 pins, while the optocoupler is generally 4 to 6 feet. Socket   Socket in electronic instruments, equipment, household appliances and other electronic products are widely used, play a role in connection. Is the modularization of electronic products, and more convenient to update, maintenance.   Socket: The direction of the socket is indicated by some special attachment number or component notch.

SMT Screen Printing Common Terms 1 open stencil area 　　 　　The sum of all image areas on a screen printing stencil. 2 open mesh area percentage 　 　　Screen all mesh area and the corresponding ratio of the total area of the screen, expressed as a percentage. 3 printing 　　 　　The use of letterpress, lithographic, intaglio, screen or other image carriers, colored or colorless media (such as ink) transferred to the substrate on the reproduction process. 4 outer frame dimension 　　 　　In the horizontal position of the screen frame, including all parts of the screen frame, including the product of the length and width. 5 printing former 　　 　　A kind of printing graphic carrier through the ink transfer will be copied to the image on the substrate. 6 printing head 　　 　　A part of a printing machine that provides the necessary pressure for ink transfer by moving against the printing plate. 7 printing ink 　　 　　A substance that is applied to a substrate during the printing process. 8 printing side(lower side) 　　 　　The bottom side of the screen printing plate, i.e., the side of the ink in contact with the substrate. 9 rotary screen printing 　　 　　The process of screen printing using a cylinder printing plate. The plate rotates in synchronization with the substrate to produce continuous graphics. The ink is supplied from the inside of the cylinder printing plate and the squeegee is mounted on the inside of the cylinder printing plate. 10 screen angle 　　 　　The angle between the main axis of a screen and the coordinate direction for elliptical dots; for round and square dots, the angle between the main axis of the screen and the coordinate direction is *smaller*. 11 screen mesh 　　 　　A carrier for screen printing stencils with regularly arranged, identically sized apertures. 12 screen printing 　　 　　The use of the printing area is screen mesh aperture printing plate leakage method. 13 screen printing former 　　 　　A screen printing plate with openings in the printing area. 14 screen printing frame 　　 　　A framing device that secures and supports the carrier of a screen printing stencil. 15 screen printing stencil 　　 　　A closed layer on the carrier of a screen printing stencil that renders the non-printing areas impervious to ink. 16 screen printing stencil carrier 　　 　　The screen portion of a screen printing stencil that carries the printing stencil. 17 screen(mesh)volume, relative 　　 　　The total volume of the mesh divided by the total area of the mesh. 18 snap-off 　　 　　Printing process, screen printing plate and attached to the substrate ink detachment. 19 squeegee 　　 　　In screen printing, a device that forces the screen plate against the substrate and transfers the ink to the substrate through the openings in the screen plate, while scraping off excess ink from the plate. 20 squeegee blade 　　 　　The knife-like part of a squeegee that acts directly on the printing ink on the printing plate to make the ink adhere to the substrate. 21 squeegee angle 　　 　　Squeegee blade tangent direction and the substrate level or with the impression roller contact point tangent between the angle, in the squeegee knife positioning after non-stressed or non-motion state measured. 22 squeegeeing area 　　 　　Squeegee in the printing plate scraping ink running area. 23 squeegee pressure, relative 　　 　　Squeegee in a section of the stroke on the plate of the linear pressure divided by the length of the stroke. 24 squeegee side, upper side of screen printing forme　　 　　Printing ink into the screen printing plate through-hole side. 25 stencil carrier area (mesh area) 　　 　　Can be made into a stencil of the screen length and width of the product. 26 stencil area 　　 　　Covering the screen printing stencil on the image elements of the squeegee stroke in the squeegee.