|Cutaway view of a flux compression generator.|
Somewhere in the last half of the book somebody sets off half a dozen E-bombs in the city which destroys all of the electronic devices and basically brings the city to a halt. People (mostly US and Soviet researchers) have been mucking about with these things since the 1950's. I don't know if anyone has ever used one as a weapon, though there was a rumor that a staged demonstration failed to stop a tank, but when the observers tried to leave, none of their cars would start. Of course, an EMP wouldn't stop a diesel powered tank as diesel engines don't rely on computers.
The big problem is we don't know what the range of such a weapon might be. Well, I'm sure somebody knows, but it's probably classified. The range of a magnetic pulse that would be strong enough to damage an electronic device might not be any greater than the size of the physical explosion. Of course, it would depend on the electronic devices. Smart phones, with their nano-scale transistors would likely be very susceptible. Anything inside of a metal box, like automobile controllers, should be immune. Lightning creates an EMP (electro-magnetic pulse), but you don't hear about everyones cell-phone dying every time there's a thunderstorm.
The only time I have seen it used effectively was in Small Soldiers . . .