[Elecraft] Humidity and ESD

[James R. Duffey]

High humidity is not guaranty against electrostatic Damage. When I worked at
Hughes Aircraft in LA, 2 miles form the ocean, we had mandatory ESD training
oncew a year. George Bryan ran it. I took the course one rainy January day.
With an ESD meter,  Dr. George measured 500 V of static electricity from a
tech putting on a non ESD treated lab jacket, and 900 V from putting an
untreated  fiberglass parts tray down on a formica lab table and raising it
up. That made a believer out of me. High humidity is no assurance that ESD
won't occur.

About 10 years later, I relocated to New Mexico. Lots of static electricity
here at any season. Now working for Maxwell, I had an engineer building a
data acquisition system for me in San Diego. I visited him one day when the
marine layer was in thick. The first thing I noticed was that there was no
anti-static pad or ESD precautions on the bench. An interesting conversation
followed:

Me: "You don't have any antistatic protection here."

Charlie: "We don't need it, the ocean is close by and it is very humid.
Static Electricity has no chance here."

Me: "What are you doing now?"

Charlie:"Changing this latch that failed."

Me: "Is it a CMOS part?"

Charlie: "Yep."

Me: "How did it fail?"

Charlie: "I don't know, sometimes these things just fail, you know like
infant mortality. It is easier to replace it."

Me: "Do you think it could be ESD?"

Charlie: "No, maybe in New Mexico, but like I said, it is too humid and we
are too close to the ocean here."

Me: "Get an anti-static pad and wrist straps."

When my colleague came back from a visit to the home office several weeks
later, he said that I had a reputation for being an ESD fanatic.

Better safe than sorry. When working with ESD parts, use anti-static
protection. Latent damage is possible; the part may fail long after it has
been hit by a static discharge. - Dr. Megacycle KK6MC/5
______________________
James R. Duffey KK6MC/5
Cedar Crest NM 87009 DM65