"One Second After"

In the book - "One Second After", the U.S. gets hit with an ElectroMagnetic Pulse (EMP) as a result of a nuclear detonation above the continental U.S. This EMP cripples almost all of the electronic circuitry in the U.S. This includes our power grid, communications equipment, GPS, etc. Anything with circuitry would basically be disabled. :shakehead

?? What would happen to an LED torch with a protected 18650 cell??

I'm in the early stages of planning how to survive such an event, whether man-made or solar induced.

My question is this: Would wrapping a torch in aluminum foil protect it from an EMP?

Yes - I realize that having my torches go out is probably the least of my problems, but in my (Law Enforcement) profession, it could be invaluable for survival and protection.

No - I'm not running around my house wearing a tin-foil hat and I would appreciate serious replies only. lovecpf

Thanks in advance,
Dave

Surely wrapping an aluminium-bodied light with aluminium foil would achieve nothing?

http://www.lessemf.com/faq-shie.html#Lead-Copper

The above link is an interesting and illustrated FAQ about EMF shielding.
Basically, aluminum doesn't work, and even copper and lead are no better!

Magnetic lines of force can't be blocked, but they can be redirected.
Iron works well for this application.

I read some where that the Arc is EMP protected as well as others. I can't find the website any more..sorry.

Faraday cage.

The answer is no. Aluminum foil is only good for protecting your brain from alien radiation... :devil:

However I've seen some studies that emp's can be avoided by something protected by approximately 2 feet of compacted dirt. In other words buried in the ground.

Anything with an IC (integrated circuit) in it would be affected by an emp, and I assume most of the modern led flashlights have them. Emp's are attracted by long strands of wire, such as power lines etc. Things that are connected to long strands of wire are most affected, but I don't know if enough stray current would affect flashlights unless they were plugged in to a charger.

Or you could build a battery powered faraday shield. That also protects against emp's.

jabe1 said:

Faraday cage.

Click to expand...

Yup, the OP should Google that.

HMMMM...I almost forgot- we all have huge Faraday cages-
our automobiles!

So keeping your flashlight in your car should keep it safe
from EMP, lightning, etc.

Of course, "Two Seconds After" the EMP hits, someone will
steal your still-working light from your car!

bob4apple said:

HMMMM...I almost forgot- we all have huge Faraday cages-
our automobiles!

So keeping your flashlight in your car should keep it safe
from EMP, lightning, etc.

Of course, "Two Seconds After" the EMP hits, someone will
steal your still-working light from your car!

Click to expand...

a car is NOT a Faraday cage. it keeps you safe from lightening because the tires insulate it.

Here's an interesting article.

http://www.futurescience.com/emp/emp-protection.html

According to him, small electronics can be effectively shielded fairly easily. I don't know what his credentials are, but it's an interesting read and makes sense to me.

Rich

A car willl work in a way similar to a faraday cage.
(must be true because it's in bold and italic, heh, heh).

The lightning will travel on the metal of the car (the easiest path,
similar to lazy me). As long as you don't touch the metal, you'll be OK.
If you do touch the interior metal when lightning hits, the tires will NOT protect you one single bit.

You will be an electrocuted ex-candlepower forum member, so
don't try it.

An EMP is a pulse, not a static magnetic field. Aluminum does an effective job of shielding against both the electric and magnetic fields of this pulsed field.

c_c

bob4apple said:

A car willl work in a way similar to a faraday cage.
(must be true because it's in bold and italic, heh, heh).

Click to expand...

sorry, no, not even close.

Ragiska said:

a car is NOT a Faraday cage. it keeps you safe from lightening because the tires insulate it.

Click to expand...

Ahem. A bit of common sense, please. http://www.mos.org/sln/toe/cage.html points out that the tyres really don't matter at all, and attributes car-in-lightning safety to something else again.

Air is also an insulator, however, and almost as good a one as rubber! If a lightning bolt has just travelled two or more miles through air, an inch or two of rubber will not make much difference. Indeed, it has been calculated that you would need solid tires about a mile thick to be safe!
...
Many people who know that it is the metal not the tires assume that the car forms a Faraday Cage, but that is also not the reason. Faraday Cages work with static electricity, lightning bolts are anything but static! The real reason is something called the skin effect.

Click to expand...

I think the same reason that it's safe to touch the inside of the cage they're playing with (or the inside of a car!) is why we only get zapped by static electricity once we get out of a car.

Cool.

Thanks, TorchBoy.

Is this post for real

To worry about your flashlight,you been on the waccy baccy.

If a UK cop wrote that he would be well !!

having seen a car struck by lighting and then hit repeadly with the high voltage power lines that fell on top of it, I can say that the metal skin of the car conducts the electricity to the ground across the tires which blew out instantly. Not touching any metal inside the car should keep you safe since the car shunts the electricity to the ground through the path of least resistance which would not be passengers inside the cabin.

An electromagnetic pulse that creates a field normally can be shunted around any object you desire with a real faraday cage or simply completely covering the item in a electromagnetic core, such as a ferrite core. Aluminum is not enough to prevent a strong magnetic field's flux lines from cutting right through it. Your not stopping the flux lines your just bending them around the core to choose an easier return path. If your flashlights and other electronic components were inside of a steel box they should be fairly well protected. Thicker steel or a real ferrite core should shield well from EMP. mu metal works great. Nickel based alloys work good. Lead will protect from radiation.

Do a search on TEMPEST shielding.

You shouldn't have any problems finding a number of mil/gov publications that will answer most (if not all) of your questions.

Because TEMPEST & HEMP shielding rely on the same basic premise (to block EM radiation) they're usually lumped together in the various pubs even though they are pursuing different goals.

EP 1110-3-2
MIL-HDBK-419A

...are good places to start.

MrGman said:

Not touching any metal inside the car should keep you safe since the car shunts the electricity to the ground through the path of least resistance which would not be passengers inside the cabin.

Click to expand...

Once again, without the Faraday cage and skin effect, it probably wouldn't matter if you didn't touch anything metal. Consider - if I'm running current through a 1 ohm resistor then place a 1 megohm resistor in parallel with it, will all the current go through the 1 ohm resistor because it's the path of least resistance? Nope. Without the physics everything inside a Faraday cage would be a conduction path. With the physics everything inside is safe. In other words, it's only if you touch the outside surface of your car that you get shocked.

Having said that, if I was in a purpose built Faraday cage or ordinary car being hit by lightning I imagine I would be staying as far away from the outside world as I could while screaming like a little girl. (No offence to little girls.)

A Van de Graaff generator works a similar way to a car getting charged up with static electricity when you move around on your seat. All the charge migrates to the outside surface of the generator dome and the inside surface and everything inside the dome has no charge.