Can 1.5 V battery kill you?

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Archimedes

Posted: Sun Jan 28, 2007 2:26 am

Guest

Hello All

I am just starting out in electronics as a hobby. I learnt Ohms law
i.e. V=I * R

Now just say I had a 1.5 Volt battery (AA cell) and an 1 ohm resistor

So given Ohms law - to find the current

I = V / R

I = 1.5 / 1
I = 1.5 amps

So can a 1.5 V battery kill you will a 1 Ohm resistor ?

Regards,
Shelton.

Wim Lewis

Posted: Sun Jan 28, 2007 2:26 am

Guest

In article <1169965586.197496.288030@k78g2000cwa.googlegroups.com>,
Archimedes <shelton.dcruz@gmail.com> wrote:

Quote:

I am just starting out in electronics as a hobby. I learnt Ohms law
i.e. V=I * R

Now just say I had a 1.5 Volt battery (AA cell) and an 1 ohm resistor

So given Ohms law - to find the current [....] I = 1.5 amps

So can a 1.5 V battery kill you will a 1 Ohm resistor ?

Not likely ... at least, not by electrocuting you.

Yes, you'll get 1.5 amps, especially if you use a kind of battery
that can produce a lot of short-circuit current (like a NiCd). It'll
generate a bit of heat. Some batteries will explode if you treat
them like this (from heat, and from gas generated chemically within
the cell). I doubt it could kill anyone, but it could injure you.
The resistor could get hot enough to give you a minor burn.

As for electrocution ... it sounds like you're under the impression that 1.5A
is inherently a dangerous amount of current. It isn't really. If you have,
for example, a 0.001-volt source pushing 1.5A through a 0.0007-ohm
resistor, that's a tiny amount of electrical power, and is unlikely to
damage anything. On the other hand, if you have 50 volts at 1.5A, that's
a good deal of power and should be treated with more care.

Your heart can be stopped by a very small amount of current ... a few
milliamps, IIRC. (Keep this in mind next time you're doing open-heart
surgery.) But that current has to actually go through your heart to injure it.
Your skin, if it's dry and not punctured, has plenty of resistance (a few
hundred thousand ohms), so it takes some voltage to force that current
through your skin. And once it's through your skin, there are plenty
of other pathways through your body besides just your heart, so
only a fraction of the current goes there. So in practice, you can
safely handle tens of volts without really worrying about electrocution.
But if you were to jab a pair of needles deep into your chest on
either side of your heart you could maybe kill yourself by attaching
a 1.5 volt battery across them. (If the needles didn't kill you
directly...)

I am not a doctor, or an expert in electrical dangers, so don't take this
post as gospel. But hopefully it will explain why people don't regularly
drop dead when handling flashlight batteries.

--
Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1

Phil Allison

Posted: Sun Jan 28, 2007 2:34 am

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169965586.197496.288030@k78g2000cwa.googlegroups.com...

** Groper alert !

Quote:

So can a 1.5 V battery kill you ..

** If you swallow it - you may choke or be poisoned.

Your mad idea is never gonna float ......

........ Phil

Archimedes

Posted: Sun Jan 28, 2007 2:47 am

Guest

Hi Phil

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?

Regards
Shelton.

Homer J Simpson

Posted: Sun Jan 28, 2007 2:54 am

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169966866.051377.268070@l53g2000cwa.googlegroups.com...

Quote:

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?

What sort of 1.5 V source?

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Phil Allison

Posted: Sun Jan 28, 2007 2:58 am

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169966866.051377.268070@l53g2000cwa.googlegroups.com...

** You need to learn proper posting style !!

Please ALTER your settings on Google Groups so that QUOTED text becomes
visible.

It is VERY bad etiquette to post on usenet with no visible hint as to whom
or which words to you are addressing.

Go to "show options" and then " reply".

Quote:

Can you please elaborate.

** Both my earlier remarks were humorous.

You thick head.

Now, do a Google search on " electric shock hazard " or similar words.

Ought to keep you out of trouble for a bit.

.......... Phil

Archimedes

Posted: Sun Jan 28, 2007 2:58 am

Guest

just a normal AA cell battery.

On Jan 28, 4:54 pm, "Homer J Simpson" <nob...@nowhere.com> wrote:

Quote:

"Archimedes" <shelton.dc...@gmail.com> wrote in messagenews:1169966866.051377.268070@l53g2000cwa.googlegroups.com...

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?What sort of 1.5 V source?

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Archimedes

Posted: Sun Jan 28, 2007 3:06 am

Guest

Thank you - yes I forgot about the resistance that the human body has
naturally.

Regards
Shelton.

On Jan 28, 5:13 pm, John Popelish <jpopel...@rica.net> wrote:

Quote:

Archimedes wrote:
Hi Phil

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?A 1.5 volt source will drive 1.5 amperes through a 1 ohm
resistance. What does that fact have to do with killing
anyone? If you have a metal joint replacement, and you run
wires in to that prosthesis, you might see something like a
1 ohm resistance, but there is probably no other way to get
a 1 ohm resistance from connections to other parts of the
body. Skin resistance is measured in the kilo ohms with 1.5
volts applied to it. You might touch a pair of ohm meter
leads to your tongue to see how low the resistance is,
there. It will be lower than across two spots on your hand,
but no where near 1 ohm.

All that said, if you insert a pair of wires into your heart
muscle, and connected a 1.5 volt battery to them, it might
cause your heart rhythm to be disrupted enough to kill you.

Phil Allison

Posted: Sun Jan 28, 2007 3:10 am

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169967966.634828.282060@h3g2000cwc.googlegroups.com...

Quote:

Thank you - yes I forgot about the resistance that the human body has
naturally.

** Top posting Google Gropers are shot on sight around here !!

Learn the etiquette !!!

Follow what others are doing if that is too hard !!

........ Phil

John Popelish

Posted: Sun Jan 28, 2007 3:13 am

Guest

Archimedes wrote:

Quote:

Hi Phil

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?

A 1.5 volt source will drive 1.5 amperes through a 1 ohm
resistance. What does that fact have to do with killing
anyone? If you have a metal joint replacement, and you run
wires in to that prosthesis, you might see something like a
1 ohm resistance, but there is probably no other way to get
a 1 ohm resistance from connections to other parts of the
body. Skin resistance is measured in the kilo ohms with 1.5
volts applied to it. You might touch a pair of ohm meter
leads to your tongue to see how low the resistance is,
there. It will be lower than across two spots on your hand,
but no where near 1 ohm.

All that said, if you insert a pair of wires into your heart
muscle, and connected a 1.5 volt battery to them, it might
cause your heart rhythm to be disrupted enough to kill you.

Don Bruder

Posted: Sun Jan 28, 2007 3:14 am

Guest

In article <1169965586.197496.288030@k78g2000cwa.googlegroups.com>,
"Archimedes" <shelton.dcruz@gmail.com> wrote:

Quote:

On the assumption that you're not just trolling, the short answer is
"possibly, but extremely unlikely in normal handling".

1.5 volts just plain isn't enough to punch through the fairly
substantial resistance presented by "normal dry skin". Since dry skin is
usually in the megohm and up range, you'd be hard-pressed to get enough
current flow out of the thing to even be noticable. At 12 volts (car
battery) while literally dripping wet due to pouring rain, I've gotten
enough of a "tingle" shock to realize that something had happened, and
everybody knows the "lick the 9-volt battery terminals to see if there's
any life in it" trick, but unless you're doing something quite unusual,
a 1.5V AA battery isn't likely to be *FELT*, let alone cause death or
any damage.

All bets are, of course, off if you sink a couple needles into your
chest to make contact with your heart, then hook the battery to them...
It's been said that half a volt at 5 mA is sufficient to throw the heart
into fatal fibrillation in a situation like that.

Your calculation forgets to take into account that there's also internal
resistance in the battery - In theory, sure, it can dump 1.5 amps. In
practice, the internal resistance will significantly limit the current
the battery can actually deliver. You're also forgetting that a AA
battery has a limited amount of juice that it *CAN* deliver - Depending
on several factors, anywhere from 1200 to 2500 mAH is a reasonably
typical rating - meaning that it can supply 1200 to 2500 milliamps of
current for an hour - or a fraction of that value for a correspondingly
longer time, or it can feed a larger draw (up to the limit imposed by
the internal resistance[1]) for a proportionately shorter amount of time
before going dead.

[1] which varies depending on several factors including which chemistry
is being used - Alkaline cells have a different internal resistance than
carbon-zinc, which have a different internal resistance than lithium
cells or lead-acid cells. The exact details of construction can make a
difference as well, so you can't say "Internal resistance of all <insert
type of cell> batteries is 'X'" and expect to have your calculations
come out right.

--
Don Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist,
or the subject of the message doesn't contain the exact text "PopperAndShadow"
somewhere, any message sent to this address will go in the garbage without my
ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info

Jon Slaughter

Posted: Sun Jan 28, 2007 5:38 am

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169965586.197496.288030@k78g2000cwa.googlegroups.com...

Quote:

No. You are not taking into account the resistance of your body. What kills
you is the current passing through your hard an interfering with the
electrical mechanisms that cause it to pump. It takes around 100mA for this
to happen if I recall correctly.

Your body has atleast 10kOhm resistance and usually much more depending on
many factors.

so if you use ohms law for 10k you'll get 1.5/10k = 0.15mA.

As you can see that is not enough to do much. You'll need atleast 100 more
voltages to get to 15mA and now you can see why the voltage inside your
house is so dangerous. Thats ~ 15mA which might not kill you but could give
you a nasty shock or burn. Ofcourse this is only your wet or sweating and
there is a path for the current to goto ground.

Remember that current must travel in a loop so you cannot get shocked by the
batter if you do not touch both ends together. You can get shocked by your
household power because they use earth ground as ground(it saves extra
wire). So you can stick your finger in an outlet if you are not in any way
grounded to earth(or even close). I wouldn't try this though if I were you.

You can safely play with very high voltage if your sure that the current is
very small. They have HV devices like the van der graaf generators that you
can touch and current can flow from you to the ground and you will get
shocked. But these are not dangerous because they have very little
current(the little current is very strong though).

Current is what kills and long as you remember that you should be fine.
Remember that current must flow in a closed path too. High Voltage though
can make current kill because the higher it is the more current that will
flow(but remember its basically ohms law that decides as it depends on
resistance too). The thing with HV is that if can cause current to jump
across things.

So if you have 1M volts then that can jump several feet across the room and
get you. Your body will take 1M/R in current. if your wet then R might be
10kOhms or smaller and you can see that that is 1kA of current. Ofcourse
things like electrostatic generators cannot produce this much current so its
not that bad. Even though your body will take that much current the general
will loose all its charge very quickly since it contains probably just a few
mA at most.

Air has a breakdown of about 30 kV/cm. That means if you have a voltage
source of 30kV then it can cross that much air to get to ground. 1M volts
means it can jump about 30cm to get to "ground".

Anyways, as you can see you don't have to wory about dieing from such a low
voltage. Just take into account your skins resistance, which you can
measure if you want, and then use ohms law and make sure you are well below
the voltage.

e.g., even 50V is only 5mA at 10kohms.

Note though that the resistance can vary a lot on the body so you should not
go plays around with the idea. Devices like stun guns are made so they
cannot put to much current out so they are usually not lethal.

Heres a site that is more indepth and explains things better:

http://www.physics.ohio-state.edu/~p616/safety/fatal_current.html

Read the bottom about skin resistances as it is what is important.

Jon

John Fields

Posted: Sun Jan 28, 2007 9:21 am

Guest

On Sun, 28 Jan 2007 06:54:47 GMT, "Homer J Simpson"
<nobody@nowhere.com> wrote:

Quote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169966866.051377.268070@l53g2000cwa.googlegroups.com...

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?

What sort of 1.5 V source?

---
He already stated what sort of source.

--
JF

chuck

Posted: Sun Jan 28, 2007 12:15 pm

Guest

Archimedes wrote:

Quote:

Your question seems to focus on direct contact with the battery and
several thoughtful answers have been provided by others.

Although not directly discussed, it may be possible to electrocute using
the energy available from a 1.5 volt battery indirectly. The voltage
would have to be increased enough to cause a current of >5 mA through
normal skin resistance, and a sufficient amount of charge would have to
be stored in a capacitor to maintain that current flow for the necessary
duration.

Common camera flash circuits achieve sufficient voltage, but would
probably need additional capacitance to provide sufficient energy for
electrocution. Each flash drains only a fraction of the battery's
capacity, but if all the capacity were stored in a high-voltage
capacitor, discharging it through your body could be fatal.

So the answer is yes, but not simply by touching the battery.

Chuck

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Homer J Simpson

Posted: Sun Jan 28, 2007 5:09 pm

Guest

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:1169967521.350224.193260@v33g2000cwv.googlegroups.com...

Quote:

Can you please elaborate. Will I not be able to produce 1.5Amps with
a 1 Ohm resistor and 1.5 V source?

What sort of 1.5 V source?

just a normal AA cell battery.

No, it won't kill you and will only deliver that current into a short
circuit and only briefly.

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