July
2005, Issue 180
Test Your
EQ
|
Answer
8—A
small CRT might run at something on the order of 10 kV,
and have an anode capacitance on the order of 1 nF. It's
easy enough to calculate the stored energy as 0.5×C×V2,
which equals 0.05 Joules. Compare this with a Tazer, which
is considered a non-lethal weapon, but typically delivers
on the order of 50 J per jolt. Even a large CRT operating
at 50 kV and having 10 nF capacitance is only storing
12.5 J.
Furthermore,
the very high voltage means that any discharge occurs
very quickly and contains only very high frequency components.
The skin effect causes these currents to flow along the
surface of the body, and there's virtually no possibility
of significant current flowing through a vital organ such
as the heart.
That's
not to say that the shock from a CRT isn't very unpleasant
to experience, and you might do some serious damage to
yourself or surrounding equipment as a result of your
reflexive reaction to receiving one!
Contributor:
David Tweed
