官方版快三  其中,年紀最小的楊成龍剛滿18歲,石發榮是家中獨子,僅19歲;祈富24歲,家中還有一個3歲的兒子;陳應幫26歲,留下了一個4歲的女兒那天,馬生珍和往常一樣,穿著干凈整潔的白襯衣、藍褲子,一雙黑皮鞋,但是“走路一瘸一拐,臉也瘦了好多”

GlossaryGlossary
Also visit our FAQsection
Active Components
Semiconductor devices, such as transistors and diodes, that can change its basic characteristics in a powered electrical circuit, such as an amplifier and rectifier.
Air Gap (Line space)
The nonconductive air space between traces, pads, conductive matter, or any combination thereof.
Analog Circuit
An electrical circuit that provides a continuous quantitative output as a response from its input.
Annular Ring
The width of the conductor pad surrounding a drilled hole. EXAMPLE: If the pad size is say, 35 mils, and the drilled hole is 25 mils then the annular ring WIDTH is 5 mils (35 = 25 + 5*2)

Annular Ring

(For PCBFABEXPRESS online special promotions, we expect your design to have annular rings which are at least 5 mils wide. If your design has annular rings less than 5 mils, we can provide you a custom quotation for your order)
Aperture
Used in photo plotting. Defines the shapes and sizes of Gerber file entities.
Artwork - CAD
Computer generated accuracy in layout used to produce a Master Pattern. Generally prepared at 1:1 scale using various software packages with special libraries of shapes to represent conductors and components and various Surface Mount Arrays.
Aspect Ratio
The ratio of the board thickness to the smallest-hole diameter of the printed circuit board.
Assembly drawing
A drawing that shows all parts identified by their reference designator (C1, R1, U1, etc. like the silk-screened artwork), panel outline with datum and tooling hole positions. If auto-insertion is required, a list of X, Y coordinates of the parts may be helpful.
Assembly File
A drawing describing the locations of components on a PCB.
Automated Test Equipment (ATE)
Equipment that automatically tests and analyzes functional parameters to evaluate performance of the tested electronic devices.
AWG
American Wire Gage. A method of specifying wire diameter. The higher the number, the smaller the diameter.
Axial Leads
Leads coming out of the ends and along the axis of a resistor, capacitor, or other axial part, rather than out the side.
"Bare Bones" PCBs
A special internet promotion that we offer for PCBs without any solder mask or legend on it.
Bare Board
An unpopulated PCB; i.e., a PCB with no components assembled on it yet. (Not to be confused with "Bare Bones", which is sometimes used to designate a PCB with no Soldermask or Legend).
Base Copper Weight
see Copper Foil.
BBT
Bare Board Test.
Beveling
Refers to the 45-degree angle that makes finger contact edges smooth, thus enabling easier insertion by the consumer.
BGA
Ball Grid Array is a leadless SMD developed in recent years. Unlike traditional SMDs, this type of device does not have pin leads. Instead it contains solder balls at the bottom of the device. These solder balls melt and make contact to the pattern on boards during assembly.
Blind Via
A via hole that does not pass completely through the printed circuit board Blind via starts from one side or another side and ends in any one of the inner layers.
BOM
Bill of Material. A component list with reference designators, part numbers, values, tolerance, description, and other information.
Break-away
A common PCB panel format with board units connected to a panel by number of tabs around the units. Units break-away from panel after assembly. Panel profiling of this format may be routed or punched.
Breakout
Poor registration between the hole and the pad on a printed circuit board to the degree that the hole is not within the area of the pad.
Bridging
A condition that generally happens during the wave soldering operation where excess solder builds up and shorts out the adjacent conductors.
Built-In Self Test
An electrical testing method that allows the tested devices to test itself with specific added-on hardware.
Buried Via
A buried via connects two or more inner layers but no outer layer, and cannot be seen from either side of the board.
Bus
A Heavy trace or conductive metal strip on the Printed Circuit Board used to distribute voltage, grounds, etc., to smaller branch traces.
Bypass Capacitor
A capacitor used for providing a comparatively low impedance AC path around a circuit element.
CAD
Computer Aided Design.
CAM
Computer Aided Manufacturing.
CAM Files
The files used for manufacturing PCB including Gerber file, NC Drill file and Assembly Drawings.
Chamfer
A shaped corner to eliminate an otherwise sharp edge.
Check Plots
Pen plots, or plotted film, that are suitable for checking and for design approval by customers.
CEM1 or CEM3
PCB material, both CEM-1 and CEM-3 are epoxy/fiberglass over a paper core, differing only in the type of paper used. These materials are less expensive and more punchable substitutes for FR-4. Not a military grade material.
Ceramic Ball Grid Array (CBGA)
A ball grid array package with a ceramic substrate.
Clearance
Separation between circuit entities. Generally refer to pad-pad, pad-trace, trace-trace, solder mask-pad, pad-drill, circuit-board edge, etc. These clearances are critical for board manufacturability and they should be set at a maximum when design allows.
Chip-on-Board (COB)
A configuration in which a chip is directly attached to a printed circuit board or substrate by solder or conductive adhesives.
Chip
The individual circuit or component of a silicon wafer, the leadless form of an electronic component.
Controlled Impedance
The process that gives a circuit the correct impedance value. The design engineer will specify the track impedance required. From this, a suitable manufacturing build will be chosen to the suit track widths and layer spacing on the design to meet the required impedance.
Coating
A thin layer of material, conductive, magnetic or dielectric, deposited on a substance surface.
Coefficient of Thermal Expansion (CTE)
The ratio of dimensional change of an object to the original dimension when temperature changes, expressed in %/ºC or ppm/ºC.
Component Side
The Side of a PCB on which most of components are mounted.
Contact Angle (Wetting Angle)
The angle between the contact surfaces of two objects when bonding. The contact angle is determined by the physical and chemical properties of these two materials.
Conformal Coat
A coating that is generally sprayed, dipped, or brushed on to provide the completed Printed Circuit Board protection from fungus, moisture and debris.
Copper Foil (Base Copper Weight)
Coated copper layer on the board. It can either be characterized by weight or thickness of the coated copper layer. For instance, 0.5, 1 and 2 ounces per square foot are equivalent to 18, 35 and 70 um-thick copper layers.
Corrosive Flux
A flux that contains corrosive chemicals such as halides, amines, inorganic or organic acids that can cause oxidation of copper or tin conductors.
Curing
The irreversible process of polymerizing a thermo-setting epoxy in a temperature-time profile.
Copper pouring or copper hatch
CAD/CAM terms. Refers to filling of an enclosed area (generally defined by 0-width polygon lines) with a solid or hatch pattern to create a copper plane or a section of copper plane.
Copper thickness and copper plating
Cooper thickness usually specified in terms of number ofoz/sq.ft (1/2 oz: 17.5um or 0.0007"/sq. ft; 1 oz: 35 um or 0.0014"/sq. ft, and etc.). The thickness of copper specified will be the final thickness of base material plus copper plating thickness. Generally base material comes with 1/4, 1/2, 1, and 2 oz, but finish copper thickness range from 1/2 to 4 or 5 oz.
Connector Tongue
A protrusion of the Printed Circuit Board edge that is manufactured to a configuration to mate with a receptacle that provides electrical and/or mechanical junction between the Printed Circuit Board and other circuitry.
Cut-and-clinch
Clinch is an operation where leads are bent at an angle after auto insertion to avoid component pop-up during wave-soldering.
Cut-outs
Removal of an internal area of the board.
DFSM
Dry Film Solder Mask
Die
Integrated circuit chip as diced or cut from a finished wafer.
Die Bonder
The placement machine bonding IC chips onto a chip-on-board substrate.
Die Bonding
The attachment of an IC chip to a substrate.
Dielectric
An insulating medium between conductors.
DIP
Dual in-line package with two rows of leads from the base in standard spacing between the leads and row. DIP is a through-hole mounting package.
Digital Circuit
A circuit comprised of mostly integrated circuits, which operates like a switch (i.e., it is either "ON" or "OFF").
Discrete Component
A component that has been fabricated prior to its installation (i.e., resistors, capacitors, diodes and transistors).
D-Code
Used in photoplotting. D-Code assignment or aperture lists are used in defining shapes and sizes of Gerber file entities.
Drill file
An NC file containing tool and coordinate information for drilling. Common format accepted are: EIA or Excellon in either binary or ASCII text file.
DRC
Design rule check.
Dry - Film Resists
Coated photosensitive film on the copper foil of PCB using photographic methods. They are resistant to electroplating and etching processes in the manufacturing process of PCB.
Dry film solder mask
solder mask film applied to a printed board with photographic methods. This method can manage the higher resolution required for fine line design and surface mount. It is more expensive than liquid photoimageable solder mask.
DXF format
Data exchange Format, commonly use in mechanical CAD systems.
Edge Connector
A connector on the circuit-board edge in the form of gold plated pads or lines of coated holes used to connect other circuit board or electronic device.
Edge Clearance
The smallest distance from any conductors or components to the edge of the PCB.
Electrical test
Electrical test or bare board test refer to PCB short/open test.
Electroless Deposition
The electrochemical deposition of reduced metal ions from an electrolytic solution onto the cathode by applying a DC current through the electrolytic solution between two electrodes, cathode and anode, respectively.
Electro-less gold plating
A gold plating process as a substitution of regular Tin/Lead plating. This type of plating applies a layer of thin gold (a fraction of micro-inches) to the entire circuit.
ENIG
A coating applied during printed circuit board manufacture to protect copper features from oxidation and provide a very flat surface for soldering components.
ERC
Electrical Rule Check verifies design violation against pre-set parameters such as In/Out matching in schematic capture, or spacing rules in CAD/CAM systems.
ESR
Electro-statically applied Solder Resist.
Etch Factor
The ratios of etch depth to the amount the resist is undercut during etching.
Etching
The process of selectively removing any material not protected by a resist using an appropriate solvent or acid.
Etch Back
The controlled removal by a chemical process, to a specific depth, of nonmetallic materials from the sidewalls of holes in order to remove resin smear and to expose additional internal conductor surfaces.
Fabrication drawing
A drawing required for manufacturing. For circuit board fabrication, also referred to as drill drawing. A fabrication drawing should include: board outline and cut-outs with datum and proper dimensions; sizes and locations of all tooling holes, mounting holes and slots; drill pattern and symbols; a drill table with tool assignment and hole specs such as size/qty/tolerance/plating; material and finish specifications; part number and drawing number (if applicable) with revision; for multi-layer the layer stack; for finger contact the beveling specs.; finally, any notes needed to clarify requirements.
Feed-Thru (VIA)
A plated through hole in a Printed Circuit Board that is used to provide electrical connection between a trace on one side of the Printed Circuit Board to a trace on the other side. Since it is not used to mount component leads, it is generally a small hole and pad diameter.
Fine Pitch
Fine pitch is more commonly referred to surface-mount components with a lead pitch of 25 mils or less.
Finger
A gold-plated terminal of a card-edge connector. Also see Gold Finger.
Fiducial mark
Fiducial marks are dots etched on board panel usually required by SMD assembly (provide viewing targets for camera to locate correct position).
Flow Soldering
Also called wave soldering. A method of soldering Printed Circuit Boards by moving them over a flowing wave of molten solder in a solder bath.
Flux
The material used to remove oxides from metal surfaces and enable wetting of the metal with solder.
FR4
Flame Retardent laminate made from woven glass fiber material impregnated with epoxy resin.
Functional Test
The electrical testing of an assembled electronic device with simulated function generated by the test hardware and software.
G-10
General-purpose epoxy/fiberglass woven fabric PCB material. Most vendors do not stock this material; instead, they use high-grade material like FR-4 as a substitution if you specify G-10.
Gen-CAM
A CAD/CAM data exchange format developed byIPC.
Gerber File
A widely accepted file format for photo plotting and is input to generate many formats of testing program and component placement program. There are two variants in Gerber file format: 274-D and 274-X (also called the extended Gerber or Gerber-X, with embedded aperture shape and sizes). PCB FAB EXPRESS accepts Gerber 274-X format only.
GI
The woven glass fiber laminate impregnated with polyimide resin.
Gold Finger
The gold-plated terminal of a card-edge connector. Also see Finger.
Glass Epoxy
A material used to fabricate Printed Circuit Boards. The base material (fiberglass) is impregnated with epoxy filler which then must have copper laminated to its outer surface to form the material required to manufacture Printed Circuit Boards.
Gold/Nickel plating
Generally required for contact fingers. Common specifications for this plating are: 0.00002" gold over 0.00015" nickel.
Grid
A two-dimensional network consisting of a set of equally spaced parallel lines superimposed upon another set of equally spaced parallel lines so that the lines of one set are perpendicular to the lines of the other.
Ground Plane
A conductive plane as a common ground reference in a multilayer PCB for current returns of the circuit elements and shielding.
Ground Plane
A condition where all unused areas (areas not consumed by traces or pads) of the Printed Circuit Board are left unetched and tied to the ground circuit throughout the board.
HAL
Hot Air Leveling, uses in conjunction with SMOBC (solder mask over bare copper), plates solder on component pads only (instead of Tin-plated traces and pad surface). Boards made toH.A.L have two advantages. First is the elimination of wrinkle effect on board surface after wave soldering (specially large copper presents). The second advantage is its ability to handle SMD assembly.
HDI
High Density Interconnect.
Hermetic
Airtight sealing of an object.
Hole Density
The number of holes per unit area on a PCB.
HPGL format
HPGL is a pen-plot format file generated from almost all CAD systems.
Impedance control
Impedance control refers to a dual process of designing and manufacturing of high speed circuit boards. As the frequency of a circuit goes up to a certain point (a few hundred Mega Hz), circuit traces will act as transmission lines and require impedance matching. With circuit of this type, trace characteristics are the function of its geometry and have to be calculated with other parameters such as material dielectric constant, board thickness and type of transmission lines; then proper trace width can be determined. Manufacturing of this circuit type requires tight control of circuit trace width.
In-circuit test
Electrical test of individual component or part of the circuit in a PCB assembly instead of testing the whole circuit.
IPC
The Institute for Interconnecting and Packaging Electronic Circuits, the final American authority on how to design and manufacture printed wiring. In 1999, IPC changed its name from Institute of Interconnecting and Packaging Electronic Circuits to IPC. The new name is accompanied with an identity statement, Association Connecting Electronics Industries.
Interstitial Via Hole
An embedded through-hole with connection of two or more conductor layers in a multilayer PCB.
IPC-A-600
An industrial grade quality standard for acceptance of PCBs.
IPC-D-356
A CAD/CAM data exchange format developed byIPC. Accepted by some CAM systems for use of photoplotting, electrical testing and other CAM functions.
Laminate
A composite material made by bonding together several layers of same or different materials.
Lamination
The process of manufacturing a laminate using pressure and heat.
Land
Land (same as pad), often referred as SMD Lands. SMD lands in most cases are suggested by component manufacturers and generally have standard codes such as 1206, SOT-23, SOIC14, etc. Consult component manufacturers or refer to IPC docs: ANSI/IPC-SM-782 for more information.
Leakage Current
A small amount of current that flows across a dielectric area between two adjacent conductors.
Legend
A format of printed letters or symbols on the PCB, such as part numbers and product number or logos.
Library
A collection of part information including symbol, foot-print, pad-stack and other cross reference information. Used in CAD/CAM EDA tools.
LPI
Liquid Photo-Imageable solder mask that uses photographic imaging to control a thinner mask deposition than the dry film solder mask.
Manufacturability
A term defining the ability of a board design to meet manufacturing requirements.
Mask
See "solder mask".
Materials for PCB
There are many different materials used in PCB manufacturing. Please see a discussion on PCB Materials here.
Master Pattern
An accurately scaled pattern, which is used to produce the Printed Circuit within the accuracy specified in the Master Drawing.
MCM-L
MCM-L is a high density interconnect device. Generally consisting of glass reinforced laminates up to 22 layers with blind and buried via technology, this product allows interconnect and attachment of bare integrated circuit die. Using a refined subtractive process, fine line width and spacing technology along with small hole drilling can be achieved. Intermediate conformal packages (e.g. DIPs, Quad Flat Packs, PGAs, SMT) are eliminated which results in size, weight, and power savings. Multiple methods of attachment of the bare die promote flexibility and reduced cycle times. Military certification is available.
MCM-L can be used where size, weight, and speed are of concern. When high density, low cost interconnections are required MCM-L packaging should be used. Space, military, commercial, automotive, and flight hardware are prime candidates for MCM-L. While limited to approximately 350 Mhz clock speed, most products can be designed into this lightweight subminiature package. Multiple methods of attaching the bare die are available, e.g. wire bond, TAB, flipchip.
Minimum Conductor Width
The smallest width of any conductors, such as traces, on a PCB.
Minimum Conductor Space
The smallest distance between any two adjacent conductors, such as traces, in a PCB.
MIL-P-55110C
A military grade quality standard for acceptance of PCBs.
MIL-STD-275E
A military grade quality standard for design layout of PCBs
mils
A unit used commonly in the PCB industry to measure traces, spaces, hole diameters etc.
1 mil = 1/1000 inch = 0.001 inch
1 inch = 1000 mils
Micro-Sectioning
A destructive test normally showing a cross section of a hole so that the plating thickness can be measured.
Minimum line space
Smallest air gap between copper features.
Multilayer PCB
Circuit boards consisting of three or more layers of printed circuits separated by laminate layers and bonded together with internal and external interconnections.
Mother Board
Also called the Back Plane, or Matrix Board. A relatively large Printed Circuit Board on which modules, connectors, subassemblies or other Printed Circuit Boards are mounted and interconnections made by means of traces on the board.
NC Drill
Numeric Control drill machine used to drill holes at exact locations of a PCB specified in NC Drill File.
Netlist
An ASCII list describes logical connections between component pins. Generated from schematic capture systems for transferring logical connections to layout systems. Other net-lists are generated from CAD/CAM systems for board test and in-circuit test purposes.
Node
A pin or lead to which at least two components are connected through condcutors.
NPTH
Non-plated through-hole.
Non-plated-through
A type of hole on a circuit board generally used as mounting holes for the board. The wall of these holes/slots are not plated thus no connection between layers.
Pad
The portion of a conductive pattern for connection and attachment of electronic components on the PCB. Also called Land.
Padstack
In CAD layout EDA systems, padstack is a collection of pad shape and size information
PCB
Printed Circuit Board. Also called Printed Wiring Board (PWB).
PCMCIA
Personal Computer Memory Card International Association.
PEC
Printed Electronic Component.
Pick-and-Place
A manufacturing operation of assembly process in which components are selected and placed onto specific locations according to the assembly file of the circuit.
Pitch
The center-to-center spacing between conductors, such as pads and pins, on a PCB.
Plastic Leaded Chip Carrier (PLCC)
A component package with J-leads.
Plating
A uniform coating of conductive material upon the base metal of the Printed Circuit Board.
PTH (plated-through Hole)
A plated hole used as a conducting interconnection between different layers or sides of a PCB either used as connection for through-hole component or as a via.
Plating Resist
Material deposited as a covering film on an area to prevent plating on this area.
Plated Holes (Plated Through Holes)
Holes with plating in them to conduct electricity, as opposed to Non-Plated through holes which do not have plating in them. Plated holes are used to connect traces across the different layers in the PCB.
Panelization
A general term in CAM editing used to prepare data in panel format.PC-103 or PC-104: A common type of solder mask, which has a shiny lighter finish than SR-1000. Generally available colors are green, blue, red, white and black.
Photoplotting or photoplot
Photoplotting is an electronic optical process to scan rasterized image data on films. Sometimes referred to as laser plotting. A photoplot is a film generated by aphotoplotter, or referred to as artwork required for PCB fabrication.
Plated-through
A type of hole on a circuit board generally used to mount components and to createvias. The wall of these holes/slots is plated forming a circuit between layers.
Prototype
Is an element of new product introduction, which involves building initial quantities, in short production runs, of an electronic product for testing, as well as for design validation and manufacturability refinement. The prototyping process involves nearly all aspects of a product prior to volume production and can significantly streamline the design and product development process, while substantially reducing costs.
Push-back
A PCB panel format with board units punched out from the panel then reset back into the same location by second operation.
Radial Lead
A lead extending out the side of a component, rather than from the end. Reference designator: Component ID used in schematic and PCB design, such as C1, C2, R1, R2, etc.
Registration
The alignment of a pad on one side of the Printed Circuit Board (or layers of a multilayer board) to its mating pad on the opposite side.
Reflow Soldering
Melting, joining and solidification of two coated metal layers by application of heat to the surface and predeposited solder paste.
Resist
Coating material used to mask or to protect selected areas of a pattern from the action of an etchant, solder, or plating.
RS-274X
A variant of Gerber data, which contains aperture shape information in addition to the usual tool selection and movement commands.
RoHS
Restriction of Hazardous Substances, is one of a handful of European legislation intended to eliminate or severely curtail the use of cadmium, hexavalent chromium, and lead in all products from automobiles to consumer electronics.
Route (or Track)
A layout or wiring of an electrical connection.
RF (radio frequency) and wireless design
A circuit design that operates in a range of electromagnetic frequencies above the audio range and below visible light. All broadcast transmission, from AM radio to satellites, falls into this range, which is between 30KHz and 300GHz.
Route and Retain
Internal routing such that PCBs remain intact on the panel for easy assembly. Later these boards are "snapped apart".
Routing
In a PCB CAD layout application, routing refers to making manual/automatic-wiring connections to logical nodes in a net. In PCB fabrication, routing refers to board edges profiling by running an NC program.
Screen Printing
A process for transferring an image from a patterned screen to a substrate through a paste forced by a squeegee of a screen printer.
Scoring
see V-scoring
Sequencing
An assembly term referring to arrangement of axial/radial components in their order of insertion sequence, and to prepare a new tape/reel by a sequencer.
Short
Short circuit. 1. An abnormal connection of relatively low resistance between two points of a circuit. The result is excess (often damaging) current between these points. Such a connection is considered to have occurred in a printed wiring CAD database or artwork anytime conductors from different nets either touch or come closer than the minimum spacing allowed for the design rules being use.
Silk Screen (Silk Legend)
Epoxy-ink Legend printed on PCB. The most common colors used are white and yellow. Also known as Legend or Nomenclature.
Solder mask (soldermask)
A non-conductive surface screened or laminated on the PCB to protect the circuit from oxidation, and shorts during wave-soldering. Common solder mask types are: SR-1000, PC-103/4,LPI.
Solder Bridging
Solder connecting, in most cases, misconnecting, two or more adjacent pads that come into contact to form a conductive path.
Solder Bumps
Round solder balls bonded to the pads of components used in face-down bonding techniques.
Solder Wick
A band of wire removes molten solder away from a solder joining or a solder bridge or just for desoldering.
Solder paste
Form of solder to be printed on SMD pads by using a stencil in assembly.
Space
See Air gap.
Small Outline Integrated Circuit (SOIC)
An integrated circuit with two parallel rows of pins in surface mount package.
SMOBC
Solder mask over bare copper.
SMD
Surface Mount Device.
SMT
Surface Mount Technology.
SMT pitch
Distance between same points on adjacent SMD pads.
Span
Refers to the center-to-center lead spacing of axial and radial components.
SR-1000
A common type of solder mask, with a darker matte finish than PC-103/4. Generally available colors are green, blue, red, white and black.
Stencil
Stencil is a cooper foil screen with SMD pads etched openings used for solder paste printing in assembly.
Step/repeat
A general term in phototooling referring to an image unit, which is stepped and repeated into multiple image units.
TDR
Time Domain Reflectometer, a device that a board house can use for measuring characteristic impedance of a conductor on a printed board, thus insuring an accurate build for controlled impedance.
Teardrop
A process for strengthening the connections between pads and tracks. Typically used when the annular ring is 0.005" or less.
Tented Via
A via with dry film solder mask completely covering both its pad and its plated-thru hole. This completely insulates the via from foreign objects thus protecting against the accidental shorts, but it also renders the via unusable as a test point.Sometimes vias are tented on the topside of the board and left uncovered on the bottom side to permit probing from that side only with a test fixture.
Temperature Coefficient (TC)
The ratio of a quantity change of an electrical parameter, such as resistance or capacitance, of an electronic component to the original value when temperature changes, expressed in %/ºC or ppm/ºC.
Test Point
A specific point in a circuit board used for specific testing for functional adjustment or quality test in the circuit-based device.
Testing
A method for determining whether sub-assemblies, assemblies and/or a finished product conform to a set of parameter and functional specifications. Test types include: in-circuit, functional, system-level, reliability, environmental.
Testability
This term defines the ability of meeting electrical requirements.
Thermal relief or heat relief
A thermal relief or heat relief is a type of circuit pad used at a location where there is a component pin or fan-out via that connects to a copper plane. The purpose of using a thermal relief pad is to provide a connection while dissipating heat through the big copper plane.
Through hole
A type of hole on a circuit board generally used for component pins andvias. The wall of these holes/slots are plated creating a circuit between layers where required.
Tin-lead/reflow
The most commonly used solder plating process in the PCB industry. The process applies 0.0004"(min.) to 0.0008"(max.) ofSn/Pb on all conductive areas. However, Tin-lead plating may not be a suitable a process if you have SMD on the board.
Tooling Hole
Also called Fabrication Hole, Pilot Hole, or Manufacturing Hole.
Turnkey
A type of outsourcing method that turns over to the subcontractor all aspects of manufacturing including material acquisition, assembly and testing. Its opposite is consignment, where the outsourcing company provides all materials required for the products and the subcontractor provides only assembly equipment and labor.
UL
Underwriter's Laboratories. A popular safety standard for electrical devices supported by many underwriters.
Via
A plated-through hole used for interconnection of conductors on different sides or layers of a PCB.
V-scoring (Scoring)
A board profiling process that involves cutting straight lines from both sides of board. This profiling method is more time efficient than a traditional routing process, suitable for medium to large volume production with panels requiring only straight line cuts. With this process, no space is needed between units.
Via
Interconnection between circuit layers. Common type of via connects traces on all layers, blind via or buried via are connected to defined layers only.
Wave Soldering
A manufacturing operation in which solder joints are soldered simultaneously using a wave of molten solder.
Warping
Warping generally refers to finished board warp and twist. All boards may have a certain degree of warp as a result of manufacturing, especially if materials contain a high volume of moisture. Therefore you should specify your warping tolerance.
Wave-soldering
A machine soldering process involving pre-heat, fluxing, soldering, and cleaning. Most commonly used solder composition is 63%Sn/ 37%Pb.
Wet mask
General type of solder mask applied by screen. Usually refers to types of solder mask like SR-1000 and PC-103/4. LPI is NOT a type of wet mask.
Wire Bonding
The method used to attach very fine wire to semiconductor components (dice) to interconnect these components with each other or with package leads. The wires might be 1 to 2 mils in diameter and made of aluminum containing 1% silicon.
Zero width
Zero width represents an outline shape drawn by "0" thickness line width. The most commonly used definition is the polygon to draw copper fill, or shapes defining the drawing limit of an entity.
Browse Our Range

排列三试机号用法

排列三试机号用法

欧冠杯即时比分  中游制造  鋼鐵:本周鋼材價格均上漲,螺紋鋼價格指數本周漲0.39%至3859.63元/噸,冷軋價格指數漲0.15%至4161.31元/噸對外破壞美國的軍事同盟關系,攪動國際秩序

排列三选胆最准的方法  在經濟上他可能會要加強監管,增加稅收,可能要投入資源來改善美國的基礎設施,以及美國的高科技的研發等等如果差距較大,也沒什么可說的,如果差距較小,每個州都有具體規定,例如差距在某個范圍內,就可以重新計票

排列三试机号及金码后  從厚厚的一摞卷宗中,家人們才了解到十七年前馬生珍兩次被綁架并最終被殺害的經過  “在進行不良資產跨境資產轉讓時,有幾點風險管理是需要注意的

欧冠比分最新張成虎不同意,此后,他每天派人來自己的礦上打砸,或拿槍威脅,逼迫自己簽署轉讓合同,導致金礦開采無法正常進行社會消費品零售總額9月同比增速3.3%,較上月回升2.8個百分點,消費整體復蘇趨勢持續加速;中游行業景氣全面上行,全球半導體銷售額8月同比增速5.9%,環比小幅回升,9月商用車銷量同比增速40.3%,新能源汽車銷量9月份同比增速繼續大幅提升至73%,挖掘機9月銷量同比增速由前月的51.3%上升至64.8%,9月重卡銷量同比增速為80.4%,較上月回升2.7個百分點;上游行業中化工景氣全線爆發,煤炭庫存持續下降

  • PCB Fabrication
  • Component Procurement
  • Assembly

官方凤凰彩票网站  4、“雙周期”配置框架:順周期+科技  “海南自貿港最大的優勢有兩點,一是稅收,境外資金跨境購買國內資產,一進一出,利潤的部分會產生稅收,海南在稅收方面的政策非常具有吸引力;二是海南省政府對金融的扶持力度非常大

排列三百位定胆法  這次,馬生珍的妻子和他一起回了西寧原有掃地機器人業務表現出色+增量業務添可在國內市場迅速起量,國內市場穩步上升,海外市場疊加疫情因素實現高速增長,未來市占率有望進一步提升;3)現金流充足,雙11在即,銷售端表現出色

购买体育彩票的app(3)科創50指數發布后個股持倉分化加劇,Q2前愈8成個股遭減持,與1年期解禁及全市場高低估值收斂有關,持股比例增加最多個股為奧特維/建龍微納/金博股份,減少最多個股為心脈醫療/虹軟科技/秦川物聯基于Q3財報和21年盈利預期,我們認為:可選消費景氣(預期)改善提速,將是下一階段“估值降維”的重要方向,同時,可選消費行業21年報較高的(預期)盈利增速彈性,也更容易誘發年末“估值切換”

欧宝体育app客户端在朱細見過馬生珍之后沒幾天,2002年4月21日,馬生珍一夜未歸,從此失聯  馬小鵬告訴新京報記者,2017年底村里換屆選舉,馬德云當選了村委會副主任,2018年原村委會主任辭職后,馬德云接任

排三排五体育彩票  馬生珍逃脫后,先報了警,然后回老家休息了大半個月,并告訴了妻子自己的經歷,他還表示,“現在錢也掙得差不多了,不想再往外跑了  1994年5月23日,甘肅省酒泉地區公安處法醫鑒定為,死者祈富、石發榮、陳應幫系他人用7.62mm槍彈射擊致死,死者楊成龍系他人用5mm槍彈射擊顱腦死亡

排列三五乐彩网目前這一數字已達到911萬,累計死亡23萬  這是朱細和馬生珍的最后一次見面

排列三试机号口决  馬生珍逃脫后,先報了警,然后回老家休息了大半個月,并告訴了妻子自己的經歷,他還表示,“現在錢也掙得差不多了,不想再往外跑了  后來,隨著青海環保政策的收緊,淘金的隊伍開始向西藏轉移,張成虎、馬成犯罪團伙也將目標瞄準了西藏

排列三必下两码技巧  10月十大金股回顧  根據每市平臺的數據統計,截止10月30日,10月金股組合累計收益為84.63%,累計超額收益68.15%,位列全市場第六名,近一個月收益-3.11%,近一周收益1.70%,10月金股中比亞迪(+36.25%)、邁瑞醫療(+13.51%)表現較好拜登也會考慮跟中國進行必要的合作

公开彩票國內經濟方面,疫情后國內經濟回升不均衡,明年經濟將切換引擎,地產拉動作用弱化,制造業投資、可選消費和服務業將成為經濟回升的主要驅動力(5)生物農業及相關產業營收環比最高,生物醫學工程產業ROE(TTM)最高,互聯網與云計算、大數據服務歸母凈利潤環比最高

更新一定牛彩票完整版這兩股分裂力量,不約而同都想通過投票來不讓對方掌權不過,我們認為,在“總量適度、精準導向”的整體思路和“降低融資成本”的長期訴求下,國內流動性環境激進收緊的可能性也較低

欧赔与亚盘的换算  2.4海外  美國:周一公布9月新房銷售75千套,環比下跌3.52%;周三公布8月原油庫存為1147.55千桶,環比減少2.37%;周四公布第三季度GDP(初值)環比折年率上升33.10%;周五公布核心PCE物價指數同比上漲1.55%  有美國精英認為,特朗普若再執政4年,美國的民主法制、在世界上的地位和影響力都會受到毀滅性的沖擊

排列三试机号乐彩网  10月A股市場走出結構性行情  陳陽表示,通過旅游消費積分交易,有效盤活境內外主要國家和地區居民海量消費積分、“喚醒”沉睡的商業價值,實現吃、住、行、游、娛、購不同商家消費積分的互通互兌,實現用戶共享、服務互通,使數字金融賦能實體經濟,促使旅游消費成為現實的生動案例和重要的金融創新

够力七星彩软件下载總體而言,國際秩序前期受到的傷害會減弱我們認為:可選消費景氣(預期)改善提速,將是下一階段“估值降維”的重要方向,同時,可選消費行業21年報較高的(預期)盈利增速彈性,也更容易誘發年末“估值切換”

排列三试机号体彩官网  楊成人回憶,沖上山去的時候,他最小的五弟楊成龍和另一位村民石發榮跑在最前面,石發榮被打中當場死亡,楊成龍的頭上也中彈,死在了去往醫院的路上  “海南自貿港最大的優勢有兩點,一是稅收,境外資金跨境購買國內資產,一進一出,利潤的部分會產生稅收,海南在稅收方面的政策非常具有吸引力;二是海南省政府對金融的扶持力度非常大

官方彩票app下载18彩金前三季度公司凈利率為27.72%,同比+3.76pct,隨著未來公司對產線的自動化化改造,降本增效效果明顯,同時未來價值量高的中大挖泵閥產品占比將不斷提升,凈利率仍有上升空間目前,上錯隆村已經選出了新的村委會主任

TOP
官方能赢钱的游戏排列三选胆最新技巧官方竞彩app下载苹果共赢彩票苹果版排列三最准胆码够力七星彩南国论坛下载