[Elecraft] ESD Risk vs Relative Humidity

[Don Wilhelm]

Wyn,

Congratulations on your moderate weather - enjoy it while you can.

It would take a large ESD surge to cause any problem with assembled
electronics, including the K2 and the XV144 - all the sensitive devices are
connected in circuit to their normal termination.

The problem during assembly IS severe - handling devices that are not
mounted can cause ESD damage to the part.  That is why one should work on a
bench with an anti-static mat and use a wrist strap when inserting active
devices into the boards.  Once mounted, the devices are not as suceptable to
static damage.

You may occasionally cause a some malfunction by a static 'zap' to the case
of the K2, but the effect would usually be transient.  In the very worst
case, one might have to do a Master Reset to recover, but that is rare and
extreme.  Even though such an occurrance is rare, it is wise to record all
your menu parameters and filter settings just in case something like that
ever happens.

73,
Don W3FPR

> -----Original Message-----
>
> What is considered a 'normal' ESD safety limit?
>
> Today in Hong Kong we have relative humidity (RH) of 55% (temp a
> 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+
>
> These past two days my daughter and xyl have mentioned several
> 'static shocks' when they play with our cats, all 6 of them.
>
> I remember my school kid days of cats tail static generators, but
> there's a serious question behind this. Under what conditions of
> RH do most builders of Elecraft rigs operate?
>
> My K2 and XV144 were constructed in spring/summer (90%+H) and
> autumn (70% RH+) with no apparent probs. Cats kept well away.
>
> I used a ESD earthed triple layer safety mat for the XV144.
>
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