1. Annular Ring

　　Refers to the copper ring that is flat on the board surface around the wall of the through hole. This grommet on the inner layer is often connected to the outside earth by a cross bridge, and is more often used as the end point or stop of the line. In addition to being used as a line pass on the outer layer board, it can also be used as a solder pad for component pin soldering. There are Pad (with circle), Land (independent point), etc. that are synonymous with this word.

　　2. Artwork negatives

　　In the circuit board industry, the word often refers to black and white negatives. As for the brown "Azo Film" (Diazo Film), it is named after Phototool. The negatives used in PCB can be divided into "original negatives" Master Artwork and "working negatives" Working Artwork after photocopying.

　　3. Basic Grid

　　Refers to the vertical and horizontal grids on which the conductor layout and positioning of the circuit board are located during the design of the circuit board. The grid spacing in the early days was 100 mils. At present, due to the prevalence of thin and dense lines, the basic grid spacing has been reduced to 50 mils.

　　4. Blind Via Hole

　　Refers to the complex multi-layer board, some of the via holes are deliberately not fully drilled because they only need a few layers of interconnection. The special hole in the dead end is called "Blind Hole".

　　5. Block Diagram circuit system block diagram

　　Frame the assembly board and various required components in a square or rectangular empty frame on the design drawing, and use various electrical symbols to connect the relationship of each frame one by one to form a systematic framework picture.

　　6. Bomb Sight

　　Originally refers to the bomber's aiming screen. When the PCB is made of the negative, the target for the alignment of the upper and lower layers is also set at each corner for the purpose of alignment. Its more precise official name should be called Photographers' Target.

　　7. Break-away panel can be disconnected

　　Refers to many circuit boards with a small area. For the convenience of plug-in, placement, welding and other operations on the downstream assembly line, in the PCB manufacturing process, they are combined on a large board for various processing. When it is completed, a knife-jump method is used to partially cut the shape (Routing) between the independent small plates, but several "Tie Bars" (Tie Bars or Break-away Tabs) with sufficient strength are retained. Drill several small holes between the sheet and the edge of the board; or cut V-shaped notches up and down, so that the boards can be broken and separated after the assembly process is completed. This kind of small board joint assembly method will be more and more in the future, and IC card is an example.

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