Xmultiple's Engineering Department

The link below of a suggested printed circuit board (PCB) layout is provide as an example to help our customers during their CAD/CAM. The questions asked by some customers is based on the suggested PCB lay-out/top view, and the example assists regarding the meaning of center line for two kinds of holes:

a.) The 0.128 inch (3.25mm) mounting hole (2 positions) represents the diameter of two holes used to mount plastic pegs, and their centering points were used as the ground “zero” for the PCB lay-out. If you take a clear look of the hole on the right hand side, then you can see there were a lot of dimensions marked the distance between holes centering points.(for both horizontal and vertical direction)

b.) For the 0.02 inch (0.51mm) dimension, it is only indicated the horizontal distance between the center of the D4 (the right-hand sided LED hole) and the center of the plastics peg’s hole (the right hand one). Once the center point of the D4 is fixed by this figure (0.02 inch), then you can go through those figures shows on the top of the drawing and get the center point of the D3 (2.54mm from D4), the D1 (13.72mm from D4) and the D2 (2.54 mm from D1) fixed as well. All other dimensions on the suggested PCB lay-out will be defined according to the dimensions away from the centering point of those plastics holes (vertically or horizontally).

c.) Because all dimensions on the drawing were figured out and to be measured from the centering point of each hole; so all pin-out will be on the center and has no chance being shifted off at all.

We hope this type of information is helpful to some companies who are not that familar with PCB layouts.