[Elecraft] ESD Safety

[Bill Johnson]

Ron,  Thank you very much for the information.  I usually work tethered to
ground with a wrist strap but also need to acquire a mat.  Since my K3 will
be factory built, I won't rush it for now.  My environment typically is 60%
humidity... sometimes higher...  my shop/shack is in the basement.  When I
start to smell mold I turn on the Dehumidifiers.  Air conditioning is
available but the who needs that when the temp is 65!

72,

Bill 

K9YEQ
K2 #35, K2 # 5279, KX1 #35, Mini Modules, etc.  



-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
Sent: Saturday, July 26, 2008 11:51 AM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] ESD Safety


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