On Tue, May 23, 2006 at 04:03:12PM -0700, Brendan Moran wrote:
> In my area, recently, there was a power surge of epic proportions.
> Someone knocked a transmission line into a distribution line.  The
> distribution grid (usually 12kV) took 60kV for a few moments until the
> safties kicked in, resulting in 600V being delivered to 120V circuits
> for a few moments.  But those few moments were enough to toast many
> appliances.
> 
> Most people lost any electronics they had connected through surge
> protectors.  They're not rated to take that kind of a beating.

Quite frankly, 600V seems like something I'd expect them to be able to
protect against just fine. What's hard about designing a circuit that
shunts that shunts that excess 500V and blows a fuse in the process? For
low voltage I've seen zener diodes used of course.

Heck, power bars get advertised as protecting against (indirect)
lightning...

> http://www.thenownews.com/issues06/052106/news/052106nn4.html
> 
> I have a friend whose parents live in the affected area.  As his dad was
> a real gadget buff, he had 3x 19" LCDs, a nice PC, and some printers.
> He had all the goodies connected through a pretty solid APC UPS.  Well,
> it cooked the input circuit of the UPS, but the equipment was undamaged.
> 
> Just another case of why your PC should be on a UPS, and why surge
> protectors on their own aren't good enough.

Scary... What would the effect be on a cheap wall wart? Almost
everything I build runs off of linear or switching wall warts. Decent
ones, bought new from digikey with the usual approvals. This goes into
my circuit through a standard linear reg of some sort.

I assume in the above instance the output of my wallwart would go from,
say, 10V to 60V which the linear reg could probably handle briefly.
Sounds about right?

-- 
pete@petertodd.ca http://www.petertodd.ca
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