🚀 go-pugleaf

In article <na.c6610c4785.a70220bric@argonet.co.uk>, Brian Carroll
<bric@argonet.co.uk> wrote:

> High output-current power sources like this, including 5V/12V computer
> PSUs, can cause severe burns if short circuited by a ring or watch strap.
> I learnt this from an old and bold computer technician who told me he
> had found out the hard way during his apprenticeship. That would have
> been when PSUs needed to deliver 100s of amps, but I wouldn't like to
> test his advice even with a modern PC's PSU.

This why REAL electronics engineers / technicians don't wear jewellery, I
once worked with a guy who was scared to death of anything over about 30
volts (bit of a problem when the kit you are working on generates 63kV), one
day he, with gay abandon, dived into a nice "safe" malfunctioning 5V unit,
very respectable bang ensued, gold wedding ring all but vaporised, finger
very nearly lost... 125Amp power supply (continuous rating - probably 200+
Amp transient)!!!

I, however, wear no rings or dangling medallions, wear a (classy) plastic
watch to work (although I don't work on anything quite that meaty these
days, I just remember the look on his face and the smell).

OTOH if I'm delving into my computers' innards there is always an
anti-static wrist strap being worn, the cost of which (about 10 quid from
Maplin if you can't nick one from work) is out of all proportion to the cost
of the damage you COULD do.

The often mentioned strategy of leaving the computer plugged in (but not
switched on) and touching the power supply casing is better than nothing but
flawed, the very moment that connection is lost, if you are wearing any man
made fibre (and who isn't) or standing on a carpet containing man made fibre
(and who isn't) you WILL generate a static charge, which could be several
hundred volts, in a frighteningly short time.

Static damage, unless severe, may not "kill" a device immediately but
degrade it such that it's life may be reduced to few hours or even a few
minutes, having seen the damage a 30nS 30V discharge did to a 5V NMOS device
I take this very seriously.

Ooh, somebody must have touched a nerve there, I don't usually get so
vociforous (sp?).
  

-- 
   _____           _         
  |_   _|__  _ __ | | ____ _     tonka@argonet.co.uk
    | |/ _ \| '_ \| |/ / _` |    Mike Curtis, ZFC A, 
    | | (_) | | | |   < (_| |    Milton Keynes again, 
    |_|\___/|_| |_|_|\_\__,_|    only temporary, maybe?