We are surrounded by electromagnetic fields.
Hollywood has done a fantastic job of creating all these doomsday scenarios where some sort of EMP device has gone off, taking out the electricity, and we are thrown back into the dark ages. How many of us would survive such a catastrophe is a huge question; however, let's bring this all back a step and explain what an EMP device really is.
Well, an EMP (electromagnetic pulse) is a wave burst of something that can be measured on the electromagnetic spectrum.
There I go again: using technobabble to explain technobabble. So, let's take this back one step further.
The electromagnetic spectrum (depicted in the image below) includes anything from radio waves, microwaves, light, through to X-rays and gamma-rays. Electromagnetic radiation is everywhere around us.
Electromagnetic Spectrum. The spectrum of waves includes infrared rays, visible light, ultraviolet rays, and X-rays. Human eyes are only sensitive to the range that is between wavelength 780 nanometers and 380 nanometers in length.
We can't see without visible light. Our bodies produce infrared radiation in the form of body heat. We've taken advantage of radio waves since World War II, and how many of us use microwaves to cook or reheat food. We use gamma-rays to sterilize our food before shipping overseas, and X-rays have become common practice within medicine. To top it all off, our modern telecommunications uses fiber optic cables to assist in sending that beloved message from one side of the world to the other. No matter how hard we try, we depend on electromagnetic radiation.
However, I believe what confuses this whole situation is all the ways in which electricity is generated. To put it simply, electricity is a gathering of electrons on a conductive surface. That's an incredibly simplistic view, but if you bear with me for a moment you'll see why I've chosen that description.
We have an EMP device in our driveways.
An electromagnetic pulse, EMP, is a short burst of whatever wave from the electromagnetic spectrum. The light bulb that dies the moment you switch it on, giving you that burst of light before plunging you into darkness, is by definition an EMP, but most won't see it that way (excuse the light pun).
The traditional understanding of an EMP is the pulse that disrupts other electrical devices. Well... The starter motor in your car is an EMP. You turn the ignition key (or push the button if you have one of those cars) and the radio temporarily cuts out, the lights go dim, and you get the lovely sparks that ignites the fuel. It's nowhere near the doomsday effects that Hollywood portrays, but that's only because very few people realize that the car is an EMP device.
Most people tend to think of weaponized devices. One of the side effects of a nuclear explosion is the gamma ray burst that results in wayward electrons playing havoc with electrical devices. Those electrons accumulate on conductive surfaces, creating a surge of electricity in the device, blowing its circuits. (Now can you see why I chose the simplistic view of electricity generation?) However, the radius of a nuclear-generated EMP is limited to the blast radius of the nuclear bomb itself. No offence, but the EMP from a nuclear bomb is actually the least of our worries. The nuclear fallout is much worse.