On Wed, 03 Aug 2011 18:56:30 -0500, "
wrote:

On Wed, 03 Aug 2011 16:46:11 -0700, John Larkin
wrote:

On Wed, 03 Aug 2011 15:07:32 -0400, Archon
wrote:

On 8/3/2011 11:39 AM, Lanny wrote:

but this resistence have a polarity?
---
No.

--
JF

They have a particular name these little resistance?

Regards


They do when I drop one and can't find it
JC


They work better at high frequencies if you install them upside down.
Less inductance.

Less inductance or higher capacitance (resistive element closer to the plane)?

What I see in a TDR setup is less series inductance. The context is a
coplanar waveguide PCB trace with a gap that's bridged by the
resistor.

ftp://jjlarkin.lmi.net/0805_res_fix.JPG

The impedance bump at cm 3.5 is inductive...

ftp://jjlarkin.lmi.net/0805_normal.JPG

and if you flip it over, it's a lot smaller

ftp://jjlarkin.lmi.net/0805_flipped.JPG


The capacitive bump around cm 1 is the SMA connector transition.

It really helps to flip them.

John