Resistor Naming Convention in EAGLE

The resistor footprints in EAGLE have cryptic names like US-0204/5, US-0204/7, US-0207/2v, US-0207/5v, US-0207/7, US-0207/10, US-0207/12, US-0207/15, US-0309/10, US-0309/12, etc.

It’s difficult to decode the naming convention. At first blush, it looks a lot like SMD resistor and capacitor case codes (0201, 0402, 0603, 0805, etc) except they don’t jibe.

Pencil on forum explains:

Example: US-0204/5 or US-204/5V
US = US symbol. Grid will be in inches (probably nearest .1 or .05 inch increment)
02 = 2mm (≈.08 inches) body diameter
04 = 4mm (≈.16 inches) body length
/5 = 5mm (≈.200 inches) lead spacing. (Note: US designation)
/5V = Vertical orientation with 5 mm lead spacing


Adjusting Solder Mask in DipTrace

DipTrace is a great schematic capture and PCB layout CAD/EDA program for Windows and Mac. It’s my go-to for quick prototype boards. The interface is more intuitive and the learning curve is far easier than any other electrical CAD/EDA tool I’ve used (Mentor, Cadence, Altium, KiCad, EAGLE).

Having said that, DipTrace does have its own quirks. Some of the finer details, like solder mask and paste mask settings, can be tricky to figure out. Luckily, the documentation and online support are pretty good.

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Sex Disparity in Tech

There have been several articles [1, 2, 3]  in the last several years about the gender, or sex, disparity in what the press refers to as “tech companies” (more accurately, Silicon Valley software companies). There are racial disparities in representation as well, but this post will focus on the gender disparity.

While the US is about 50/50 male/female (48.9% male, 51.1% female in 2016 via Wolfram Alpha), the breakdown of college degrees is not.

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Linux which, Windows where

On Linux command line, the which command will help you find which executable is tied to a shell alias. For example, if you want to know what python executable is being called when you type python on the command line, you can do

$ which python

and it will print out the path to the python executable.

On Windows command line (cmd.exe), the analogous command is where
where python

This doesn’t work for builtin shell commands like dir (Windows) or cd (Linux) because they don’t actually point to an executable anywhere in the file system, they are built in to the shell.

Managing Path Environment Variable from Windows 10 Powershell

Things are a bit different on Windows 10 Powershell compared to the plain old cmd.exe of yore.

In powershell, here is what you do if you want to view the contents of your Path variable. First, open up a powershell terminal. Then, enter the following command:

> echo $env:Path

The contents of your Path variable will be printed to the terminal. You can also just type > $env:Path.

To change the Path variable, you can assign to it using the equals sign:

> $env:Path = "foo"

Don’t worry, doing this will only change your Path for the current Powershell. If you mess something up, you can open a new Powershell and it will have the default Path setting.

If you merely want to append (add) to the existing Path variable, you can do it like so:

> $env:Path = "$env:Path;foo"

This command will append foo to the Path. The semicolon ; is the path separator on Windows systems.

5 Useful Windows 10 Virtual Desktop Shortcuts

Here are some super-useful keyboard shortcuts for working with Virtual Desktops on Windows 10:

Ctrl + Win + D: Create a new Virtual Desktop

Ctrl + Win + Right/Left Arrow: Switch to next/previous Virtual Desktop

Win + Tab: Task View, then Tab to highlight your Virtual Desktops, Ctrl + W to close the selected one, or Enter to switch to it.

This one requires some explanation: The Task View shows all your open windows laid out in a tiled fashion, similar to Alt + Tab. However, you can take your fingers off the keys after pressing Win + Tab and the Task View remains active and, furthermore, the open windows are shown across all monitors on your system (so you can see which windows are on which monitors).

From Task View, you can also manage your Virtual Desktops. At the bottom of the screen, you will see all your Virtual Desktops. If you only have one desktop, you will only see a “New Desktop” button in the lower right. By pressing the Tab key, the cursor will move down to the Virtual Desktop area and you can then use the arrow keys to highlight a Virtual Desktop. With a Virtual Desktop highlighted, you can then press Ctrl + W to close it, or press Enter to switch to it.

Windows 8.1 Drivers for Brother HL-5250DN

I had a little trouble installing the correct driver for the printer but eventually got it to work — here is how it went.

The manufacturer says the driver is already included with Windows OS:

brother HL-5250DN driver 01

However, I could not complete the driver setup instructions because the setup program (Add Printer) hung when I clicked on the “Windows Update” button, as directed.

So, as a first workaround I did the following:

  • I chose from the “generic” list of Brother drivers the one called “Brother Laser Type1 Class Driver.”

This worked just fine for a few prints I needed to do before I found some time to troubleshoot.

Later, I opened up the printer properties window and clicked the “New Driver” button:

brother HL-5250DN driver 02

Then, find and click “Brother” in the Manufacturer list. Then click “Windows Update.”

brother HL-5250DN driver 03

Wait a minute or two for it to finish downloading the drivers, and then the Printers list should show a bunch more drivers. Find “Brother HL-5250DN” and select it, then proceed through the rest of the dialogs to finish it out.

Once that is done, you should be back in the “Properties” dialog window. Make sure to click OK or Apply so that the new setting is saved.