Anyone with Roger's Lite accounts?

[James Knott]

Paul Sutton wrote:
> When I was at college we were told that it's the current (Amps) that
> actually kills you,  in the Uk the mains is 13 Amps, not sure what it is
> in the USA / Canada, also the Root Mean Squared on the 50 hz frequency
> means that you multiply this 240 volts by 1.414 (I think).

While it is the current that kills, it won't flow without the voltage to
push it.  In a resistive circuit, current is prortional to voltage.

> 
> We were also told that 50 Hertz (hurts) 60 Kills either as a way of
> remembering the differnt frequencies or perhps that 60hz is more
> dangerous, so perhaps the RMS on 60hz is higher,  We also covered 3
> phase in the UK which is 415 volts and a higher current, certainly ovens
> here are at 30 AMPS.

RMS (root mean squared) is independent of frequency.  It's the
equivalent DC value, that will carry the same amount of energy.  With
sine waves, it's 70.7% of the peak voltage.  If you want, you can go
back to calculus to work it out.

> 
> Regarding fire if you short a 9v battery with a screwdriver and say left
> this in a pile of paper, (stupid I know), it could catch fire, which is
> why you have to be careful with such equipment this can be done
> accidently i.e drop battery, and it lands somewhere and shorts,
> Any comments, can anoyne clarify this.

The battery would have to produce enough current, to create sufficient heat.

> 
> 
> what does GFI mean? I will try and find out if we use it or not,

Ground fault interupter.  It measures the current in both the hot and
neutral wire.  If unbalanced, it assumes there's a fault (such as
through someone) and kills the circuit.  They are required by law near
sinks and outside.
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