PCB Tech - PCB circuit design terms

Annulus Ring 1

Refers to the copper ring that is flat attached on the PCB board outside the hole wall. This ring on the inner plate is often connected to the outside earth by a cross bridge, and is more often used as the end of a line or crossing station. On the outer plate, it can be used not only as the passing station of the line, but also as the welding pad for the pin welding of parts. The word is synonymous with the word "Pad", "Land", etc.

2. Artwork film

In the circuit board industry, this word often refers to black and white film. As for the brown "Diazo Film" (Diazo Film), another name is Phototool. The negatives used for PCB can be divided into "original negatives" Master Artwork and "Working negatives" Working Artwork after turning.

3. The Basic Grid

Refers to the circuit board in the design, the conductor layout location of the vertical and horizontal grid. The early lattice spacing was 100 mil, but now the basic lattice spacing has been reduced to 50 mil due to the prevalence of thin and dense lines.

4. Blind Via Hole

In a complex multilayer plate, some of the through-holes are deliberately not fully drilled because only a few layers of interconnection are needed. If one of the holes is connected to the ring of the outer plate, such a special Hole like a cup-shaped Blind alley is called a "Blind Hole".

5. Block Diagram

The assembly board and the required various components, in the design drawing to square or rectangular empty box to frame, and with a variety of electrical symbols, the relationship of the box one by one contact, so as to form a system of architecture.

6. The Bomb Sight

The sight screen from which bombers drop bombs. PCB also sets these two layers of alignment in each corner of its film for alignment purposes, which is more precisely formally known as Photographers' targets.

7. A Break-away panel

Refers to a number of small circuit boards, in order to facilitate plug-in, placement, welding and other operations on the downstream assembly line, in the PCB process, specially combined on a large board, for various processing. When completed, local Routing between independent small boards is conducted in ** mode, but several "Tie Bar" or break-away Tab of sufficient strength is retained, and several holes are drilled between the connecting plate and the edge of the board. Or the upper and lower cut V notch, to facilitate the assembly process after the completion of the board can be broken apart. This kind of small board child union assembles means, will be more and more in the future,IC card is an example namely.

8. Put a Hole together and bury it

Refers to the local through hole of the multilayer board, when it is buried in the inner layer of the multilayer board becomes the "inner through hole", and is not "connected" with the outer plate, called the buried guide hole or referred to as the buried hole.

9. The Bus Bar

Refers to the cathode or anode rod itself, or the cable to which it is connected. In addition, in the "process" of the circuit board, the outer edge of the finger is close to the edge of the board, and the original one is connected with a universal wire (to be covered during gold-plating operation), and then a small narrow piece (to save the amount of gold so as to minimize its area) is connected with each finger, this kind of electric wire is also called Bus Bar. The small piece connected to the Bus Bar by each individual finger is called Shooting Bar. When the board finishes cutting the shape, both will be cut off.

10. CAD computer aided design

Computer Aided Design uses special software and hardware to carry out digital Layout of circuit board, and converts digital data into original film by optical plotter. This kind of CAD is far more accurate and convenient than artificial way before making the circuit board.

11. Central-to-center Spacing

In terms of Nominal Distance from centre to centre of any two conductors on the finger board surface. If the conductors are continuously arranged with the same width and spacing (such as the arrangement of gold fingers), the "distance from center to center" is also called Pitch.

12. They have Clearance

Refers to the inner layer of the multilayer board, if you do not want the conductor surface and through the hole wall connectivity, can be through the hole around the copper foil erosion and the formation of empty ring, especially known as "empty ring". The distance between the green paint on the outer panel and the rings is also called Clearance. However, as a result of the current board line density gradually improve, make this green paint original room was also tight * to almost no.

13. Component Hole

The through-hole for the pin insertion of the fingerboard. The average aperture of the pin hole is about 40 mil. With the advent of SMT, the number of large hole jacks has gradually decreased, only a few gold pin holes of connectors still need to be inserted and welded, and most other SMD parts have changed to surface bonding.

14. Component Side

Early in the circuit board all through the hole insert times, parts must be installed in the front of the board, so it is also called the front of the "component surface". The opposite Side of the plate is also called Soldering Side because it is only for Soldering tin. Currently, SMT boards have to be bonded on both sides of the parts, so there is no "component side" or "solder side", can only be called front or back. The name of the manufacturer of the electronic machine is usually printed on the front, and the UL label of the circuit board manufacturer and the date of manufacture may be added on the back of the board.

15. Spacing between conductors

Refers to a circuit board surface of a conductor, from its edge to the edge of another nearest conductor, covered by the insulating substrate surface span, that is, conductor spacing, or commonly known as spacing. Also,Conductor is a general term for the various forms of metal conductors on a circuit board.

16. Contact Area resistance

On the circuit board is specifically refers to the gold finger and connector contact point, when the current through the resistance presented by that. In order to reduce the formation of oxide on the metal surface, usually the positive part of the gold finger and the negative clip of the connector should be plated with metal to reduce the occurrence of "load resistance". Other electrical plug into the socket, or between the guide pin and its seat also have contact resistance.

17. Corner Mark

On board negatives, special marks are often left at four corners as the actual boundaries of the board. If the inner edge of the mark is connected, it will be the boundary line of the Contour of the completed plate.

18. Deep reaming, Counterboring hole

The circuit board can be locked and fixed in the machine with screws. The non-conductive hole (NPTH) of this match must be made to accommodate the "reaming" of the nut, so that the whole screw can be sunk into the surface of the embedded board to reduce the obstruction caused by the appearance.

19. There are many Crosshatching areas

Some large area of conductor area on the circuit board, in order to get better adhesion between the board and the green paint, often turn off the copper surface of the sense part, and leave a number of crisscross cross lines, such as the structure of the tennis racket, so will solve the large area of copper foil, due to thermal expansion and the existence of floating from the crisis. The etched shape of the cross is called Crosshatch, and this improvement is called Crosshatching.

20. Countersinking cone hole, horn hole

It is another kind of screw hole used for locking. It is commonly used in carpentry and furniture, but less often in the precision electronics industry.