[Techtalk] Re: Electrical hacking

[Helen]

    I have to come out of lurking for this one.  I was originally a hardware
electronics technologist starting in the mid 70's. Very few females in the
field at that time.
    AC will make you stick and high voltage DC will throw you across a room.
My worst experiences were with a VHF transmitter  and 700VDC and an FM
transmitter at 110VAC. Both were with the power supplies of the equipment,
after the first main transformer.  I am still here to talk about it though.

Helen

----- Original Message -----
From: "Conor Daly" <conor.daly at oceanfree.net>
To: "Techtalk" <techtalk at linuxchix.org>
Sent: Sunday, April 13, 2003 2:18 PM
Subject: [Techtalk] Re: Electrical hacking


> On Sun, Apr 13, 2003 at 01:55:46PM +0100 or so it is rumoured hereabouts,
> Maria Blackmore thought:
> > On Sun, 13 Apr 2003, Conor Daly wrote:
> >
> > > Things you just don't touch:
> > >
> > > o High voltage stuff inside your sick monitor (see [0]).
> >
> > Not actually that bad, since it's quite low current, there are a number
of
>
> But doesn't it take only a few milliamps to kill?
>
> > > o The wiring in gadgets in your bathroom (see [0] also).
> >
> > Once again, perfectly safe, so long as you know what they do[2], why
they
> > do it[0] and how to avoid making them not do it[3]
>
> Given the above, it's perfectly safe.  It _is_ vital though to understand
> the interaction between electricity and water and how really really
> important that little rubber seal that just tore was...
>
> > > Things I have successfully fixed:
> >
> > I've never let the fact that I've never done something from stopping me
> > doing something.  I think this is a very important thing that other
people
> > should do, too.  Take the knowledge you have and extrapolate it, reuse
it
> > as appropriate, and use it to find what you don't know.
>
> Agreed.  I enjoy reverse engineering tape decks, VCRs etc.  The above is
> one of the main things holding poeple back in all sorts of fields.  Once
> you overcome the fear of being unable to do something, there's pretty much
> nothing to stop you.
>
> > It's important to challenge yourself, it's how you learn.
>
> yep
>
> > > Of course, the other thing to remember is the cost efficiency.  How
much
> > > is your time worth?  Will you spend more time fiddling around than you
> > > would spend in cash on the ready made device.
> >
> > Ah, yes, the bane of the throw-away society :(
>
> That's something that really bothers me.  I bought a new car exactly once
> and that was through work with some major discount included.  My current
> car is 11 years old and I plan to keep it for another 15 or more.  I had
> to tear myself away from an old oscilloscope (dunno if it was working) in
> the skip recently 'cos I _knew_ that it would sit in the attic forever
> more "just in case".
>
> > Maria
> >
> > Who does this for fun, and profit[4] :)
> >
> > [2] It's an isolating transformer, to isolate the socket from you in an
> > electrical sense, it makes the power coming out of the socket on
> > the two pins relative to each other instead of to ground, this means
that
> > it's safe to connect one pin from the socket to ground through yourself,
> > and not get hurt.  Of course you'll still get a jolt if you connect
> > yourself between the two pins, but this is covered by the Being Bloody
> > Stupid Act. :)
>
> Ah so _that_ how they work!  I've seen these and understood the notion of
> them isolating the user from the mains supply but I was never clear on
> exactly _how_ they do it.  The transformers you see on building sites and
> used by trades people work similarly:  They have a transformer with a
> centre tap (which AFAIK is connected to ground) and 55VAC available off
> either end of the transformer.  This supplies 110VAC to the tool but
> nowhere is there more than 55V above ground so shock hazard is very low.
>
> > [4] I've worked as a sparky in a theatre, as local crew, assistant, and
> > occasional sound engineer in various venues, and as an engineer in a TV
> > station
>
> Did/do you see much sexism in those fields?  You're in the UK yes?  Here
> in Ireland, there seems to be much less of a barrier to women than I've
> heard cited on these lists though the various motor workshops I've worked
> in/visited did tend to have the ubiquitous girlie pinup calender hanging
> up somewhere...
>
> Conor
> --
> Conor Daly <conor.daly at oceanfree.net>
>
> Domestic Sysadmin :-)
> ---------------------
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