Topic: EMP question

[VANGUARD]

I'm having a hard time finding an answer to this. In the game, Call of Duty: MW2, Captain Price launches an EMP missile (or two), and disables an area on a country. Naturally, all electronic devices no longer works.
Question is,

"After" this has been detonated, can anything electrical work when you enter that area, or is there something in the air that will disable it for a certain period of time?
I'm not asking for any lengthy reply. Short and sweet works for me.

[TechPro]

An EMP is an electromagnetic pulse, which you could also describe as a large (or larger than normal) burst of electronic 'noise' or a pulse of electronic energy.  It is brief (hence the word 'pulse').  Only "knocks out" stuff that isn't sufficiently protected and only stuff that is present at the time of the pulse.  Anything brought in afterwards is not affected.

A common example is a lightening strike which creates a fairly small EMP in the area of the strike and is felt by electronics as a jolt or power surge/spike that can disrupt radio signals briefly, and disrupt your electronics if they are not shielded and will destroy the electronics if not sufficiently surge protected.  Simple surge protectors are usually not enough.  The effect is brief and may last longer if the pulse is stronger, but still temporary.  Any lingering effects would be electrical charges left from the pulse that hasn't dissipated.

[VANGUARD]

so let's say a game, or a movie would find some way to fire off one of these EMPs in an area; they could charge right afterwards and take them out with all of their electronics working?

nice. thanks!

[TechPro]

That's correct.

You've seen Independence Day?  At one point they fire off a nuke at an alien ship with a armored vehicle nearby to observe the result.  The blast shakes the vehicle around a bit and their electronics gets zapped a bit, but because they were shielded, they simply restarted their electronics and as the blast wave dissipated, they were able to use their electronics.  Sure, it was Hollywood hamming it up, but pretty close.  Just had to wait for the initial charge/shock to dissipate.

[-<WillyP>-]

Of course that doesn't mean the creators of COD implemented it that way. I would think a popular game like COD you who find plenty of information specific to the game.

[karx-elf-erx]

An EMP doesn't only "knock out" insufficiently protected electronics. It destroys them by overcharging them. Since an EMP is a super intense "flash" of electro-magnetic energy, it's duration is only very short. After it has gone, it leaves nothing behing that could damage electronics any further. So you can safely enter an area that had suffered from an EMP even with unshielded electronics afterwards.

[VANGUARD]

Thanks all for the info. Really cool stuff. That was one question on my mind for some time.

Saw that movie years ago. Is that when they demonstrated on shooting a pop can near the ship?

[NUMBERZero]

No, they drove a SAM truck up to monitor the detonation of a nuke on a mothership launched by a B-2.

[Scyphi]

But they did shoot the pop can, too, that was just a different scene.

[VANGUARD]

But they did shoot the pop can, too, that was just a different scene.

That was the scene I was asking about, some demonstration.

[Matthew]

That scene had nothing to do with EMPs, though.

[VANGUARD]

That scene had nothing to do with EMPs, though.

hm....that had to do with shielding then right?

[Scyphi]

And catching colds.

[Matthew]

That scene had nothing to do with EMPs, though.

hm....that had to do with shielding then right?

Yes but not the kind of shielding we're talking about with EMPs. There was nothing to do with EMP in that movie other than as a very minor footnote of the nuke. EMP shielding would be a metal enclosure designed to conduct the charge away from the electronics.

[DarkWing]

Or just good grounding for the circuits (routing unwanted charges away from the circuits is what grounding does, in addition to helping to stabilize electronics).