[sebhc] [Fwd: ANSWER: General Comments from Mouser website.]

[Lee Hart]

Carroll Waddell wrote:
> Some H8's may have had gold contacts, but the 3 that I have all had tin
> plated contacts.

The first H8's had tin plated connectors. Heath (mistakenly) thought
they could get away with the cheaper tin connectors. They were wrong.
The tin connectors had intermittents and were a reliability headache.
Later models used gold plated connectors.

Tin *does* work for connectors *if* certain conditions are met. First,
you need high contact pressure; tin oxide is soft, and the high pressure
breaks through the oxide film to make connection in spite of the oxide.
Second, you want redundant contacts; more than one path for the current
(for example, a contact that pinches the pin from two or more sides). As
long as either point of contact connects, you have continuity. Third,
you need a minimum of voltage and current to break down the oxide film;
tin works poorly below 10 milliamps and 1 volt.

As it turns out, NONE of these conditions were met by the H8 connectors.
Thus, tin was a terrible choice.
-- 
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net


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