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Re: [Amps] 200 Watt Fast Relay

To: Bill Fuqua <>
Subject: Re: [Amps] 200 Watt Fast Relay
From: Larry Benko <>
Date: Tue, 10 Jul 2007 12:43:58 -0600
List-post: <>

A lot of small relays especially with bifurcated contacts (2 contacts 
side by side with a small amount of give to each one) also have a 
minuscule amount of wiping between the contacts upon closure.  The 
combination of gold clad silver and this wiping allows the relay specs 
to allow use in circuits of 1 uA or less although testing is usually 
done at the 10 uA level.  My experience is with non-RF applications at 
current levels below 1uA with no issues of contact oxidation.

Larry, W0QE

Bill Fuqua wrote:
> 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. Naturally in a vacuum 
> any good conductor can be used in the contacts  because oxidation can't 
> form with our air. Years ago it was suggested that as long as the relay had 
> a set of contacts that rub as they close,  this friction would break thru 
> any crusty oxidation and clean the contacts. But, I can't see that working 
> 100% of the time.
> 73
> Bill wa4lav
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