Bang&Olufsen began using silver plated boards as early as 1960 for their
recorders! I've such a one. Stood unused in our attic for 20 years. I took
it down, removed all dust and plugged it, started and worked perfectly! Do
you know the secret? I know, because I worked as a connector and relay
specialist for a couple of years. Gas tight contacts!! If you have a
gastight contact, you have a reliable connection for many years. So, it's
not only a question of silver thickness, but contact design and pressure.
This about board connectors. Switching, that's something quite different.
Much more complicated. You need to know about contact sphere, burrs, silver
thickness, power to be switched, interrupt time, mechanical force, contact
sliding, spring reliability and a lot more. If you really is involved in
switching, I recommend you to contact a person with such profession. A lot
of failures have disappeared because of better components and bette
technology, but switching problems remain still and is costly and annoying.
Don't experiment with switching if you don't have knowhow in this area! I
don't have any names because I left that field 25 years ago, but I guess
some are still there, like Amphenol, Leach, etc. Here comes, for your help,
some of the better known. If this isn't enough, I've two hundreds more.
Good Luck
Inge
3M
A-B (Allen-Bradley)
A-MP
A.B. Dick Co.
A.H.& H.
A.W. Haydon Co.
ACM
ACME
Acra Electric Corp.
ADC
Addressograph Corp.
Aerovox
Airpax
AIV
ALCO
ALL
Allied Moulded, Ohio
Alps, Japan
American Tack & Hardware Co. Inc
Amerock
AMF
AMP
Amphenol
Amron
Anchor Wire Corp.
Apollo Corp.
Applied Motion Products, Inc.
Ark-Les, USA
ARO Corp.
Arrow England
Arrow-H&H
Artisan
AS
ASA JAPAN
Astron
AUGAT
Autoclave Engineers Inc.
Autorol Corp.
Autotronics, Inc.
AVC
Barber Coleman Co.
BARCO
Basler Electric
BBC
Beau USA
Beckman Instruments, Inc
Bel
Bendix
Berger Lahr
Bourns
Brainerd Mfg. Co.
Bramco Controls Div.
Breter
Bristol Motors
BRK Japan
Brooks Instrument Div.
Bryant
BT
Buchanan
Buehler Products, Inc.
Burgess England
Burndy
Buss
C&K
C-H
Calectro
Calif. Computer Products, Inc.
Callins
CANAL
Cannon
Canon
Carling
CGW
Cherry Electric
Chicago Switch
CIMCO
Cinch
Circuitrim
CKD Controls Limited
Claro
Clarostat
Clifton Precision
CM
CMS
Coat & Clark, Inc.
Coilcraft
Components Corp.
Computamite
CONAX
Conquer
Conrac Cramer Division
Continental Connection Corp.
Control Components, Inc.
----- Original Message -----
From: "Wayne Thayer" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, September 14, 2006 7:03 PM
Subject: Re: [TN] Silver Oxide and Contacts
>I believe most mechanical switches use silver plated contacts, but
> that's an entirely different surface finish than the ImAg you are
> working with--its just a point that silver is OK for switch contacts. I
> know ImAg is designed as a temporary coating and is ultra-thin, so if I
> were you I'd also be concerned about long term consequences. Here's
> another data point--I've recently purchased two different PC
> motherboards and both appear to have ImAg board finish, as can be seen
> by the support mounting holes, which didn't receive any solder. If
> that's true, than somebody must think that ImAg is not likely to cause a
> problem if left exposed within the life of a PC.
>
> Wayne Thayer
>
>>>> [log in to unmask] 9/14/2006 1:09 am >>>
> We've been using Immersion Silver instead of HASL for several years
> now.
>
> A new design has connector pins that are held to the surface of the
> board
> with springs, so there is no solder, just connector contacts touching
> SMT
> pads.
>
> The silver pads are starting to tarnish,
> but I have heard that silver oxide is conductive.
>
> My questions are:
> How Conductive?
> Is there going to be resistance?
> Is silver okay for switch contacts?
> Does Immersion Tin corrode the same way?
> Do I need to go back to HASL on this one?
> (or is gold not a cost adder anymore?)
> Is this too many questions?
> Should I stop now?
>
> thanks in advance?
> Jack
>
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