31 Dec '14, 6pm

The myth called "ground" via /r/TheAmpHour

The myth called "ground" via /r/TheAmpHour

For example, let's take a microstrip trace over a metal plane, but let's have a PCB stack up where the metal plane is assigned as 3.3 V (not "ground"). A ground plane will exist lower in the PCB stack. The schematic will indicate the return current path is ground, not 3.3 V. Unfortunately, the current does not read the schematic to see where the designer intended the current to flow. It will follow the path of least impedance. At frequencies higher than about 1 MHz, this means the path of least inductance. That path will nearly always have the smallest current loop size, so the current will flow on the 3.3 V plane, not the ground plane.

Full article: http://www.edn.com/design/test-and-measurement/4437986/Th...


Task force denies reports #US engaged in ground combat with #IslamicState in #Iraq

Task force denies reports #US engaged in ground...

stripes.com 23 Dec '14, 5am

In this file photo from Sept. 28, 2008, infantry Marines make sure their weapons are in working condition at Al Asad Air B...