EMP blast - what would happen really?

I've heard that if an EMP weapon were used, *nothing* in the blast area that relies on electricity would work.

Is this really true?

If you had an alkaline battery, it would still put out a voltage, correct?

Failing that, one could still take a roll of paper towels, immerse the towels in a salt solution (table salt should do), place alternating plates of copper and zinc (or any two dissimilar metals), and obtain a current... right?

Would motors still work, or would their windings be guaranteed destroyed in an EMP blast?

Thanks,

Michael

Reply to
mrdarrett
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Michael - The EMP (electro-magnetic pulse) would not affect batteries. In fact, it's really only a concern for IC's, especially microprocessors. The big deal several years ago was that U.S. military aircraft relied heavily on silicon ICs and microprocessors, but the stone-age Soviet planes were still using vacuum tubes and the vacuum tubes would be pretty much immune to a nuclear EMP. The EMP problem goes back to Einstein, et. al. wherein a wave can also be an atomic particle, which is true of course, and can, and does occasionally knock out one bit of a memory cell, usually in spacecraft. However, the caveat being that the nuclear blast causing the EMP doesn't evaporate you and your battery cell, thereby leaving you no reason to worry abut the EMP :)))

Almo

Reply to
almo

After an EMP event, batteries will still hold their chemical charge, electrical motors will still function (except, perhaps, for the smallest micro-motors), relays will still function, as would electron-tubes. The power grids will see a major overload, and protection circuits will "kick" in. Whether they recover in a timely manner is another subject.

What will be damaged are most unprotected electronic circuits: Consumer electronics, TVs, radios, cell phones, iPods, Blackberries, hand-held video games, home computers, etc. Even automobiles have so much electronic gear (computers, sensors) that they would be rendered useless after an EMP event. This is one [small] reason I keep a 1969 Chevy truck -- no electronics.

The key is the threshold energy: motors, generators, transformers, relays, power-grid components, vacuum tubes all operate in the range of

10 milliJouls to >1 MegaJoules, while all consumer electronics (integrated circuits) have a threshold energy at or below 1 milliJoules (down to 100 nanoJoules and less). EMP pulses can produce 10 milliJoules inside of electronic circuits, and 100 Joules outside of electronic enclosures.

The majority of military electronic gear has protection circuits built-in so they would survive (at least they are designed and tested that way).

Reply to
tlbs101

Almo, you are confusing two very different things.

EMP is not an atomic particle sort of wave, but instead is essentially a very powerful radio wave. It induces current in antennas - intentional ones, and also any conductor that it encounters. When it hits the huge antenna that is the electrical power grid, it can be powerful enough to fry "big" things like motors, but when it hits smaller conductors it can induce enough to fry sensitive things like IC's (which often are more electrically fragile than tubes). The power of the pulse-induced current does the primary damage, though there could perhaps be some secondary effects.

But you've mixed it up with the effect of individual charged particles, such as from radioactive decay or cosmic sources, on very small structures in IC's. That's an entirely different matter - it cuases erroneous operation and flips flip flops, but it usually non-destructive, unless it triggers self-distructive current flow from the ordinary power supply by putting an IC into latch-up.

Reply to
cs_posting

Spot on.

A US test once knocked out street lighting in Hawaii !

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Graham

Reply to
Eeyore

So vacuum tubes (and diesel generators) should still work... and here I thought we'd have to go into hydraulic gates (some researcher in MIT was working on these, I can't find the link at the moment) in the event an EMP went off...

Thanks,

Michael

Reply to
mrdarrett

Scrub that last link. There's loony stuff later on written by right wing nitwits.

Graham

Reply to
Eeyore

Andy comments:

After reading the replies to your question, I am afraid that they have missed the point.

The answer is , NO, you would not be able to download p*rn until you bought a new computer.......

Sorry, ;.... but that's the fog of war.....

Andy in Eureka, Texas

Reply to
AndyS

Porn, ha ha... they can use the analog solution: magazines.

I was more concerned with the future wars our administration will get us into, but that's a whole 'nother story. In that case, the supply chain involved with "buying a new computer" may not exist...

Cheers,

Michael

Reply to
mrdarrett

As you suspect, the statement that after a detonation of an "EMP weapon", "nothing with 2 asterisks" in the "blast area" that "relies" on electricity would work is a bit inaccurate and/or misleading. Much electrical and electronic equipment already in existence would be destroyed or damaged. Some would not. This undamaged equipment would work fine after the pulse had gone by. Yes of course an alkaline battery would still put out a voltage. If it was in a circuit it might have got fried first. Of course if you made a voltaic pile out of wet tissues and dissimilar metals it would work. An EMP device does not abolish electric currents for ever within the blast area.

If by an "EMP weapon", you mean a nuclear device optimized for EMP (all nuclear weapons produce EMP to some extent), they work by sending out an electromagnetic pulse which would induce more or less heavy currents in conductors. This could damage electronic equipment and electric power lines, generating stations and substations.

The resistance to EMP by device is listed below, from most to least vulnerable:

  1. Integrated circuits (ICs), CPUs, silicon chips 2. Transistors 3. Vacuum Tubes (also known as thermionic valves) 4. Inductors, motors

Transistor technology is likely to fail and old vacuum equipment survive. However it must be considered, that different types of transistors and ICs show different sensitivity to EM: bipolar ICs and transistors are much less sensitive than FETs and especially MOSFETs.

To protect sensitive electronics, a Faraday cage must be produced around the item. This can be done by wrapping the item, such as a radio in foil (any external connections should not touch foil) without any holes. This will shield the item from EM fields.

So you can see that motors are fairly low down the list of vulnerable equipment.

A strike *guaranteed* to burn out the windings in an electric motor would most likely destroy the building it is housed in by blast or heat anyway.

When a defecting (for money) Soviet pilot landed a MiG fighter in japan towards the end of the Cold war, and US techs stripped it down, they laughed at how "backward" the Soviets were, still using vacuum tubes in the 1980s. Such dinky little tubes as well. Then they stopped laughing when they noticed a couple more features and realised they were looking at a practically EMP proof plane.

Reply to
mike.j.harvey

and it would put this guy out of business

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martin

Reply to
martin griffith

In message , dated Mon, 14 Aug 2006, snipped-for-privacy@gmail.com writes

Hard copy.

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John Woodgate

Before, or after?

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Michael A. Terrell

During.

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Reply to
John Woodgate

Wat would you think happens if 10000+ volts is induced in every meter of wire? Suddenly like with lightning, every computer,tv etc being blitzed, power lines evaporating, and all technical installations going to their last reward. All done by exploding a nuclear device just above the atmosphere. Some such damage seems to have occurred ,with a test explosion from th USA,frying the electric net on an island in the pacific. What happens is,atoms get separated from their electrons,causing the transportation of a huge amount of charge(like in lightning) only much worse,and it works best,if the radiation front hits the atmosfere from above. So yes, your battery keeps working, but your radioantenna or your headphone wire picks up enough to blow your radio. Isolation on the wiring in motors is the first to go,unless the motor is not connected to anything.

Reply to
Sjouke Burry

I just saw one of those programs on the telly where lotz of americans get killed by a tornado then get saved buy the fire department and there were some really good shots of the electricity stuff blowing up and the bloke in charge said he knew there were people dieing out there when he saw that.

Anyway, I wondered why he didn't phone up the electricity company and ask them to switch it off before it got there. Then all of the electricity stuff wouldn't have blown up and all those americans would not have died.

DNA

Reply to
Genome

I thought I went out of my way to point out the "confusion" part. Although, true, it has been a matter of debate for a long time, nonetheless; is light a wave or a particle? Is light considered electro-magnetic energy?

Reference Wikipedia - "In physics, wave-particle duality holds that light and matter exhibit properties of both waves and of particles. It is a central concept of quantum mechanics. The idea is rooted in a debate over the nature of light and matter dating back to the 1600s, when competing theories of light were proposed by Christiaan Huygens and Isaac Newton. Through the work of Albert Einstein, Louis de Broglie and many others, it is now established that all objects have both wave and particle nature (though this phenomenon is only detectable on small scales, such as with atoms), and that quantum mechanics provides the over-arching theory resolving this paradox."

Almo

Reply to
almo

Well, I just zapped a door handle with 18,000 volts. Not even a mark on the door handle. Somehow you are confusing volts with energy. There is very little relationship. How often do you blow your hand off due to static electric discharge? Voltage without other parameters tells us nothing - but can be used to hype junk science claims on the naive and those who blindly believe Rush Limbaugh.

Having asked questions such as why, then that 10000+ volts induced one meter of wire means nothing. I discharged 18,000 volts in only

0.003 meters - much more intense electric field - and I am still here to talk about it.
Reply to
w_tom

Eh? EM radiation is ONLY a photon. Not only that, those released from an EMP have very, very low energy (even the very light you're reading took only a few volts to create, and that has a frequency in the exahertz range).

"Atomic" particles (presumably, those with mass which the world is built from) have a quantum mechanics wavefunction. They do NOT necessarily interact as EM waves do, because they aren't the same damned particle!

And BTW, Einstein hated quantum physics, and it was DeBroglie besides.

Tim

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Reply to
Tim Williams

'Cept it doesn't happen. Think about it. Fuses on every pole.

...Jim Thompson

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Jim Thompson

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