When a bomb explodes, the pressure wave breaks things. An EMP is an electromagnetic wave that breaks things because like a normal explosion, the pressure/voltage is too much for the target.
But science fiction ignores the issues of scale. Lightning strikes create some very strong EMPs but they only effect things very close to the strike. An atomic blast creates an EMP but you probably don't care much about the EMP if you are anywhere near an atomic blast. Any EMP device that doesn't explode has to be as big as the area it effects so you would have to put it on top of the thing you want to damage.
As far as I know, it's just a giant burst of radio waves, strong enough to induce significant voltages and currents in metal objects. If that happens to a wire connected to the input of some electronics, the overvoltage will get into the semiconductors and capacitors and either burn out components by thermal effects from too much current, or punch-through insulators and semiconductor junctions by overvoltage.
Basically, the large changing electromagnetic fields will induce a voltage on the wires or circuits, resulting in voltages that would damage the ICs in the electronic devices.
How much damage would occur...depends on how close you are to the event and how much shielding the device has. You should store any valuable electronics in a fully shielded copper room deep within a mountain....like the US does.
Comments
When a bomb explodes, the pressure wave breaks things. An EMP is an electromagnetic wave that breaks things because like a normal explosion, the pressure/voltage is too much for the target.
But science fiction ignores the issues of scale. Lightning strikes create some very strong EMPs but they only effect things very close to the strike. An atomic blast creates an EMP but you probably don't care much about the EMP if you are anywhere near an atomic blast. Any EMP device that doesn't explode has to be as big as the area it effects so you would have to put it on top of the thing you want to damage.
As far as I know, it's just a giant burst of radio waves, strong enough to induce significant voltages and currents in metal objects. If that happens to a wire connected to the input of some electronics, the overvoltage will get into the semiconductors and capacitors and either burn out components by thermal effects from too much current, or punch-through insulators and semiconductor junctions by overvoltage.
Here is some good background on the phenomenon.
http://www.fas.org/nuke/intro/nuke/emp.htm
Basically, the large changing electromagnetic fields will induce a voltage on the wires or circuits, resulting in voltages that would damage the ICs in the electronic devices.
How much damage would occur...depends on how close you are to the event and how much shielding the device has. You should store any valuable electronics in a fully shielded copper room deep within a mountain....like the US does.