OT: UK to move back to imperial units?

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

ENIG is easy. One can indeed mask over vias. Done right, the vias are pretty small to start with. No, a masked via is not going to leach solder during reflow. This isn't HASL.

You want ideas on PCB design look at the board on hard drives. Millions are produced and they push power elements so heat gets generated, but they are very good at managing it well, so one would think that thos thin PCBs are designed pretty good. Look at their techniques.

I would trust methods implemented by say Seagate long before any "I've done it for years" guy that maybe did 50 boards in his life. Those guys at Seagate have decades of experience through decades of PCB fab evolution as well. Hell they probably fab their own PCBs in house.

In chemistry class in highschool I was handed a nickel spatula for use in some experiment (throwing salt crysals into a bunsen flame perhps) it was stamped with the words "PURE NICKEL" and was dull grey in colour.

It stuck to the magnet in my pencil case.

There should be nickel foil inside NiMH batteries.

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

Forced surface oxidation. Then, it is a known 'patina' and less mutable. Less so than Copper is even. RF coils in mil radios get this treatment

BTW 'pure' Silver oxide can be made even more conductive than the Silver itself.

Note that those few percent are enough to get the guys making power feeds to robot wheel motors from Silver cable links, so it must matter to them thar MIT robot boys.

Hmm nickle plated steel.

George H

Nevertheless, silver plating the wire used in the roller coasters and other inductors of linear amps is a common practice among RF power amplifier builders.

However, measurements of attenuation in waveguides have shown that plain copper is better then silver plated copper. This is thought to be because the plated finish has more surface roughness. Polishing doesn't help because the polishing process worsens the conductivity of the silver despite improving the surface smoothness.

John

We used to solder mask over vias; not masking is fairly new here. The un-masked vias are easy to probe, or to blue-wire to. They look great too.

We do mask the microvias under a BGA.

Cursitor Doom wrote in news:qi1sv5$vpo$ snipped-for-privacy@dont-email.me:

It isn't "nevertheless". It works better, period. Especially at those frequencies where some signals move around on the skins of the conduction links.

Bitching about percentage numerics. 6% is 6%. More is more... less is less. More conductive is better for power.

Likely also less noisey at the very least for RF.

For DC, screw plating, get solid silver strands made into a cable. That is for high power apps. Or hard forged silver links.

That's on account of contact resistance. Silver oxide conducts pretty well; copper oxide doesn't.

There's an electroless silver plating product called Cool-Amp that is intended for contacts but which I use on the family silver (mostly platters, which take a lot of wear). ;)

Cheers

Phil Hobbs

But of course our job is to make a thing as good as it can be, and still within cost and production goals. Not every product needs or can afford its own cryo-cooler, so SMD thermal technique is quite useful.

I made a spreadsheet that calculates d.c. and thermal resistance of via fields, including empty and solder-filled vias. Lead-free solder-fill cuts the thermal resistance of a .5mm 3/4oz-plated via roughly in half; of a .25mm via by about a quarter.

->| |

Nah, Always Wrong / Missing Prong's another guy, presently using another nym. Easily identified by the potty talk.

CD's just a humble U.K.er, whom Hillary would call 'deplorable,' possibly 'irredeemable.' :-)

Cheers, James Arthur

snipped-for-privacy@yahoo.com wrote in news: snipped-for-privacy@googlegroups.com:

I am not androgynous. ALL of my posts, regardless of the nym, are easily ID'd, and no, it does not require "potty mouth", you immature twerp acting punk. You should refrain from jumping on that hayride, child. You know it is beneath you.

The spreading resistance is a killer there -- there's no easy fix besides putting the vias under the device(*), which is why solving this is rather interesting.

• Well, okay, 1mm Cu buss bar might do a fair job.

Cheers, James Arthur

That won't stand. The Constitution sets the requirements for president, and California is not allowed to change or add new requirements.

Cheers, James Arthur

I don't carry a cell phone. I just don't feel the need to be interrupted 24/7 yet, somehow.

I'm a cell-phone Luddite.

Cheers, James Arthur

Apologies. I'd meant to not dox you, didn't mean to offend.

James Arthur

Yeah, I get interrupted a lot. Maybe two or three phone calls a month and a few texts a week from my wife. OTOH, it allows me to work when away from my desk, in addition to being damned handy as an e-reader for those times when I'm forced to wait for others.

Apparently.

James Arthur may not be a nitwit, but he's certainly right-wing. Cursitor D oom reliably posts orthodox right-wing nonsense, which happens to be neithe r entertaining or hetrodox - I call him a gullible twit.

Cursitor Doom's electronics-related posts are remarkably infrequent, and ju st as worthless as his political propaganda.

Quite how James Arthur knows that he isn't a Russian troll isn't clear - pe rhaps James Arthur is one himself. James Arthur has admitted to being a pai d lackey of the Koch brothers, which is not something one would expect of a Russian troll, but a multi-tasking consultant would be able to serve more than one customer at once.

The linux guy used to call himself Massive Prong, which I morphed into Mini Thong, and finally settled on Always Wrong. I think he's the same guy, likely a tech. His style is distinct, probably not C.D.