[Elecraft] ESD Safety

[Elliott Lawrence]

Even with all of the ESD controls in place, the mil specs require the 
assembly operation to shut down if the humidity goes below 25%!!!

Elliott WA6TLA

----- Original Message ----- 
From: "Rick Dettinger" <k7mw78 at gmail.com>
To: "Ron D'Eau Claire" <ron at cobi.biz>
Cc: <Elecraft at mailman.qth.net>
Sent: Saturday, July 26, 2008 10:03 AM
Subject: Re: [Elecraft] ESD Safety


> Looks like the only solution is to work under water.  All of the  voltages 
> exceed the 30 volts  or so level we have heard cause damage  to sensitive 
> components.
>
> 73
> Rick Dettinger   K7MW
> ====================================
>
> On Jul 26, 2008, at 9:51 AM, Ron D'Eau Claire wrote:
>
>>
>> This is a subject that comes up here regularly among those working on
>> their Elecraft (and other) rigs.
>>
>> Doing some research on a project, I ran across the following values
>> published by Hewlett-Packard Company. They provide some insight about
>> why it's important to use ESD-safe handling procedures.
>>
>> The "PCBs" mentioned below are, of course, Printed Circuit Boards, not
>> the stuff found in old capacitors and transformers. "DIPs" are Dual
>> In-line Pin integrated circuits such as found throughout Elecraft  rigs.
>>
>> Typical Electrostatic Voltage Levels
>>
>> Relative Humidity for each voltage level shown below:
>> 10%
>> 40%
>> 55%
>>
>> Walking across carpet
>> 35,000 V
>> 15,000 V
>> 7,500 V
>>
>> Walking across vinyl floor
>> 12,000 V
>> 5,000 V
>> 3,000 V
>>
>> Motions of bench worker
>> 6,000 V
>> 800 V
>> 400 V
>>
>> Removing DIPS from plastic tube
>> 2,000 V
>> 700 V
>> 400 V
>>
>> Removing DIPS from vinyl tray
>> 11,500 V
>> 4,000 V
>> 2,000 V
>>
>> Removing DIPS from Styrofoam
>> 14,500 V
>> 5,000 V
>> 3,500 V
>>
>> Removing bubble pack from PCB
>> 26,500 V
>> 20,000 V
>> 7,000 V
>>
>> Packing PCBs in foam-lined box
>> 21,000 V
>> 11,000 V
>> 5,000 V
>>
>> Ron AC7AC
>>
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