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Re: [Amps] 200 Watt Fast Relay

To: <amps@contesting.com>, "Bill Fuqua" <wlfuqu00@uky.edu>
Subject: Re: [Amps] 200 Watt Fast Relay
From: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 10 Jul 2007 17:58:05 -0400
List-post: <mailto:amps@contesting.com>
> Here is a problem I have with relay specifications. 
> Usually, for weak
> signal applications we use gold plated contact switches 
> and relays. Since
> most relays or switches are normally exposed to air, 
> oxidation can form and
> weak signals can't always be conducted between them.

Unfortunately you can use any plating you like and a 
percentage of relays will eventually mess up if it has 
exposure to "air".

The most common problem for sealed relays (not vacuum, just 
enclosed) is contamination caused by the materials in the 
relay. It's a tiny layer just a few molecules thick.

That's why the contacts have to wipe, or have a small amount 
of current when closing.

Vacuum relays cure that problem.

73 Tom 


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