Member Project / Space Upgrade: Giant 7 Segment clock!

With wireless programming, custom PCBs, and an amazing viewing angle. Good work!

The little gerber viewer that could!

Of course I’m talking about gerbv! For those of you who don’t know, gerbv is a free Gerber or RS-274X viewer that comes from the gEDA Project. It’s free, it’s open source, it’s cross platform… (quick link to windows version download here) and that’s awesome.

So, why do you care? Well, if you are building your own circuits and want to get a PCB made then usually the format you’ll need to export your design into is a gerber. The reason you should grab gerbv is to double check for errors. When you design a PCB in your favorite circuit layout tool, whether it be Eagle, Altium, or my favorite DipTrace, you should double check for errors.

The copper layer thickness in a printed circuit board (PCB) is rated in ounces (also called the copper weight) or in mils (also called the copper thickness.) Both units of measurement are relaying the same information just in a slightly different format. For example, 1 oz. of copper is equivalent to 1 square foot of 1.4 mils (.0014″) thick copper.

Copper weight/thickness is important in several areas of PCB design. The thickness and width of a trace determines the amount of current (amps) the trace can carry. The thickness is also used in the calculation of trace impedance (ohms) in RF and high speed digital circuits.

The following is the formula for cpw (in oz) to thickness (in mils) conversion:

Thickness(in oz) = thickness (in mils) /1.37

The following is the formula for thickness (in mils) to cpw (in oz) conversion:

t ( in mils) = t ( in oz) * 1.37