We were learning about AC/DC circuits, and I was wondering if what I am
thinking is correct, or am i missing something.
If i had a resistor of at least 40K connected to the wall socket (120
vac) in series, I would not get an electric shock if i touched the end
of the resistor (hence creating a complete path)?
Is this how the testing equipments work, the ones to test if there is
current on a wire?
Thanks in advance,
On 8/3/05 7:40 PM, in article
In theory and most of the time you will not get a shock. But resistors can
fail or be contaminated with water or something else. It is also possible to
misread what is actually a 40[ohm] resistor as a 40K resistor and end up
getting unpleasantly surprised.
I do not understand your last question. What kind of test equipment are you
There are some testing equipments, such as a "neon tester"
which does use a resistor in this way. But, the resistor has
been designed to work at that voltage, has been tested at
that voltage and is enclosed in a protective container that
should stop it getting damp or contaminated with something
that may be conductive. With the advent of cheap
electronics, they have been replaced by non-contact
detectors that use electronics to sense the presence of
voltage on the wire. This has the added advantage, as well
as safety, that you don't have to strip the wire insulation off.
Normally, never rely on a single device to protect you - it
may have a manufacturing fault, been damaged or simply (in
this case) got damp or wet. It could be a cheap copy from
(insert name of your favourite country). You can tell old,
bold electricians by the presence of the belt and the braces...
So, if you really want to try this in practice - get your
teacher to try it first. Oh and make sure he hasn't got a
wooden leg and is hopping at the time..Which reminds me of
Oh, and do a Google on Darwin Awards.
Assuming you are connected across 120V with a 40K resistor in series the
current would be a little under 3mA. The table I have shows the
threshold of perception of shock at about 1mA and painfull shock at
about 9mA for men, about 2/3 of those for women.
One way of identifying the hot conductor is to connect one lead from a
neon test lite to the hot and hold the other lead. Even without being
grounded there will be a capacitive current and the neon light will
light very dimly. Even when connected directly across 120V the current
through these testers is very low, I think less than 1mA.
Sounds to me like a mind-experiment question. I can't quite picture
anyone trying it.
> the current!
> V/R = I I*R = V
> EZ stuff, doesn't know that, should not play with wall sockets.