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Current running through headphone cord?

G

gigajosh

Could someone please enlighten me as to whether or not there is a
current of any strength passing through the cord of a set of ordinary
stereo headphones.


/very curious...
 
S

SQLit

gigajosh said:
Could someone please enlighten me as to whether or not there is a
current of any strength passing through the cord of a set of ordinary
stereo headphones.


/very curious...

of course there is, it is electricity after all. As to the amount it is very
low I do not know what the exact value is. I sure would not sit in a bathtub
and wear them. I am a bit paranoid about electricity and water. I will not
even swim in a pool with the light on.

Just for fyi
all values in milliamperes
1 threshold of sensation
2 mild shock
5 gfci will trip
10 can not let go
20 muscle contraction
30 suffocation possible
100 heart stops beating
300 severe burns/ breathing stops
1000 will light a 100 watt lightbulb

Just my view from the cheap seats
 
P

pkh

I wouldn't worry about sitting in the tub and listening to headphones
from a battery powered portable CD player or radio! Most run off of two
AA cells, and 3V isn't going to do squat to you! If your radio/player
plugs into the wall, well then that's another story...

It's the current that kills you, but it takes a good amount of voltage
to get it through you!

Just my $0.02!

Paul
 
C

Caleb Hess

I wouldn't worry about sitting in the tub and listening to headphones
from a battery powered portable CD player or radio! Most run off of two
AA cells, and 3V isn't going to do squat to you! If your radio/player
plugs into the wall, well then that's another story...

It's the current that kills you, but it takes a good amount of voltage
to get it through you!
Dry skin = high resistance = low current.

But wet skin = low resistance = high current. Also large surface area
implies lower resistance. I recall a story from my college physics prof
about an electrocution involving salt water and a single dry cell.
 
P

pkh

Wet skin will be lower resistance, but still not enough to make a 3V
dangerous. Your physics prof was having some fun with you ;) . Salt
water has higher conductivity than pure water, but now the dominant
current path is through the salt water, not you.

Wet your hand and put some ohm-meter probes on it an inch apart and
measure the resistance... I=V/R... how much current will that 3V put
through you??? And this is just a 1 inch section of the skin on your
hand, to be lethal, the current path must travel through your chest
cavity... hop in the tub and grab an ohm-meter probe with each hand and
see what your resistance is... (well, that's a pain to try, but it
should more than an order of magnitude higher than the single hand test).

BTW, my tried and true method for testing a 9V battery is to put my
tongue on the terminals... :) if it's a little painful, it's got some
life left in it, if it just tingles a little, it's spent! Now if my
tongue were only long enough to test my car battery... ;) .

Regards,

Paul
 
J

John Wilson

Guy said:
Try putting each hand in a seperate bucket of salt water at different
potentials. Believe it or not, people used to do this on purpose;
There is a scene showing it in the movie _The Road To Wellville_.




..then you could join the rock band KISS...

I've seen an old (1920s) electrician's handbook that describes tasting
as a standard way to test for live low-voltage circuits. For 120V and
240V power, they describe something I've seen (and cringed at), namely
checking for voltage by licking two fingertips (on the same hand!) and
putting them on the terminals. The book mentions that some men* find the
shock from doing this at 240V to be too much for them. And if they're
standing in a puddle while they're doing this ...

*At that time, they didn't even consider the possibility that an
electrician could be a woman.

73,
JohnW
 
R

Ross Mac

So true! I recall reaching across the desk where I caught two chassis's,
both on unpolarized plugs, and only one with a grounded neutral. I made up
the difference...that would be 110vac back then!....Ross
 
J

John Wilson

Floyd said:
That does seem to be a reasonable assumption though, right?

Do you know any women _*dumb*_ enough to do that?

I've read some of Dalziel's papers from the experiments he did at
Berkeley that pretty much established the "standard" values for things
like let-go current. This is the guy who invented the GFCI, among other
things. His experiments involved having students hold an energized wire,
then attempt to let go, and the range of values he published have been
used ever since in electrical safety work. He was able to get the male
subjects to make it a competition, so they really tried hard and would
put up with extreme pain to show that they could handle a stronger shock
than the next guy. This gave him good data on let-go currents for men,
at least for men of grad-student age. He complained that he couldn't get
as good data for women, because they weren't interested in outdoing each
other, and would do one or two tests, then decide enough was enough.
His photos of the expressions and body contortions the tests put his
subjects into make it clear that you don't ever want to experience a
shock anywhere close to let-go current.

The standard assumptions for electrical safety still show lower let-go
currents for women than men, and it's still not known whether women
really are more likely to freeze onto a live conductor, or whether
Dalziel just proved that women are smarter than men.

73,
JohnW
 
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