PCB Copper Weight / Thickness Chart

Layer Stack

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

Weight Thickness
1/2 Oz. .7 mils
1 Oz. 1.4 mils
2 Oz. 2.8 mils

 Copper Weight / Thickness Chart

Voiding a warranty on an external hard drive

After a recent hard drive failure, I realized I need to start doing some proper backups (Duh, right?)  Anyway, while shopping for hard drives to build a backup NAS (for which I need some internal drives, not external USB drives) I discovered a trend where a lot of external hard drives are cheaper than internal drives at the same capacity. How does this make sense?

I ended up purchasing these 3TB hard drives for about $140 each at Office Depot.  It’s a crap shoot on which hard drive will be inside, but it will normally be made by the same manufacturer, and be of that capacity. (You would be surprised to find out this isn’t _always_ the case).

Being a 3TB Seagate, a quick search over at Newegg shows this drive which sells for $229.  That’s a $90 dollar difference.  WOW!  So doing this instead of buying internal drives is a bargain so far.

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Sequence Animoog on your iPad from your PC with Fruity Loops over WIFI

animoog screenshot

Just playing around with the iPad app Animoog, which I believe is still available for $0.99 at the iTunes app store. This is a huge bargain on a really really cool app.  I won’t get into the specifics of the app, but if you want to know more about what Animoog is or how to use it, I recommend this YouTube video.

So, while playing around with the Animoog app, if you go into the setup menu there is a selection under ‘Refresh MIDI input(s)’ where  you can select ‘Off’ or ‘Network Session 1′.  This intrigued me!  Apparently you can use MIDI over the ‘Network’.  After some Googling I was still unclear on how to get this setup, so I thought I’d just tell everyone how I did it so you can get to making some cool tunes yourself.

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Getting started with CPLD’s and FPGA’s

Chris has been dabbling with CPLD’s and FPGA’s.  He wanted to share some helpful resources with anyone else looking to get started with them as well.

IKEA weekend light fixture hack

In my sons nursery, we have the changing table against the wall.  The problem is the only light in the room is in the middle of the room from a ceiling fan.  So basically while your changing him you are blocking the light with your body.

So me and the wife went looking for a light to add to his changing table, we found one at IKEA that we like but it’s a ceiling mount light with 3 individual 35 watt flood bulbs, with cartoonish fish as the housings.  I’m not about to drill a hole in the ceiling and install a wall switch (as the instructions state it’s supposed to be installed), so we looked around for something else but nothing caught our eye.

I decided to just get this fixture, and hack it.

In the lighting section of IKEA they have some DIY lamp kit, I just needed a cord since I’m going to be plugging this in the wall, and they’re pretty cheap.  So I grabbed the neon green one since it looks cool.

First thing I did was open everything up to see what we are dealing with…

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