Electromagnetic pulse An electromagnetic pulse , commonly abbreviated to EMP , is a burst of strong electromagnetic energy . An EMP can be generated in numerous ways , from industrial accidents to specially - designed generators . However , EMPs are best known from their first documented source : nuclear weapons . As the primary effect of an electromagnetic pulse is the destruction of electronic elements , there are some weapons that generate it , used primarily against various robot s . These include the pulse grenade s and the pulse rifle prototype developed by the Reaver Movement . While similarly named , the YK32 pulse pistol , YK32 pulse rifle are not EMP weapons but generate an electrical pulse effective also against living targets . Discovery and history . The EMP effect was discovered in the earliest days of nuclear testing , and was observed during the Trinity test , mankind ' s first nuclear detonation . However , scientists of the day were more concerned with the physical effects of the weapon and less so with the electromagnetic consequences , so the field remained largely unstudied until after the conclusion of World War II . As scientists began to research the EMP phenomenon , they began to hypothesize that the EMP could serve as much as a weapon as the brute destructive forces of the bomb itself . While the primary effects of a nuclear weapon would continue to remain the overpressure and thermal effects , the EMP was nevertheless recognized as a useful secondary effect . An EMP can also occur in a non - nuclear environment . These NNEMPs ( non - nuclear electro magnetic pulse ) can be generated by high frequency microwave generators or by flux compressors , but their range and effectiveness are limited in comparison to nuclear EMPs Characteristics . The term " EMP " is a catchall term for any strong burst of electromagnetic energy , regardless of the source . Generally , however , an EMP is a very brief event , lasting less than a second . However , much happens in that span of time . An EMP is actually the combined effect of three distinct pulses , each operating over a different duration and at a different speed . The first pulse , called the E1 pulse , is the fastest component and arrives first . This is an electrical pulse , and is capable of inducing very high voltages in conductors in a thin fraction of a second . This leads to overloads in everything from substation transformers to microchips , making the E1 pulse the most damaging element of an EMP as far as electronics are concerned . The sudden voltage spike , exacerbated by long high - power transmission lines or similar antenna - like structures , can easily cause fires in utility transformers and will burn the delicate logic switches inside solid - state electronics , rendering them useless . The E2 pulse , second to arrive , is actually the weakest in terms of causing damage . Its characteristics in conductors are very similar to those found in a lightning strike , making common surge - suppressor technology quite effective in arresting its effects . Any electronics that survive the E1 pulse will likely survive the E2 . The third and final pulse , E3 , appears only during an EMP generated by a nuclear blast ; only a nuclear weapon creates an E1 pulse strong enough to cause an E3 . A nuclear weapon ' s E1 pulse is actually strong enough to deform the Earth ' s magnetic field , its E1 pulse creating a " bubble . " As the E1 pulse dissipates , the Earth ' s magnetic field " snaps back " to its proper field lines , creating a pulse of its own . This is the E3 pulse . Effectively , the E3 pulse is an " echo " of the E1 . Like the E1 , the E3 pulse induces severe voltage loads in conductors , quite akin to the effects of a severe solar flare . Large utility grids are particularly vulnerable to the E3 pulse as the long " high - tension " carrier lines naturally attune and undergo induction . Transformers somehow spared by the E1 pulse can very easily fall victim to the E3 . Effects . The damage wrought by an EMP , whether created through nuclear or non - nuclear means , varies with the object being bombarded . Transformers and electrical switching gear tend to suffer most from the obscenely high voltages induced in conductors . This high degree of induction is more than capable of causing transformer coil ruptures , casing bursts , fires , and other damage . Switching gear can burn or spot weld . Arc shorting is easily possible across phases in a transformer substation , causing yet more damage . Solid - state electronics , such as microchips and integrated circuits , suffer severe damage from the inductance pulse . Microminiaturized transistor s , which ordinarily operate in the range of millivolts , are suddenly exposed to energies exponentially greater than design or even tolerance levels , leading to the abrupt destruction of the logic and memory elements of the electronics . For humans , however , an EMP is usually absolutely harmless , often even undetectable . Unless a person has an implanted device , such as a pacemaker , an EMP will usually pass by unnoticed , save perhaps for a slight tingling sensation . This is emphasized in the pulse grenade / mine damage to organic targets in " Fallout 3 " . The only damage from the grenade is possibly the shrapnel . Owing to " Fallout ' s " timeline split , the integrated circuit revolution never really took hold . The proliferation of vacuum tubes in the classic Fallout games ( " Fallout " and " Fallout 2 " ) is explanation enough for the survival of the computer consoles and Pip - Boys . " Fallout 3 " is more of a departure from the original motif , emphasizing small - scale electronics and powerful computers , but conventional EMP shielding methods can explain the survival of these devices . Mitigation . Electronics can be shielded from the effects of an EMP , but effective shielding is difficult to achieve and can be quite costly depending upon the application . Generally , EMP shielding takes the shape of some form of Faraday cage , a giant mesh antenna which grounds incoming signals , inside which the system to be protected lives . Mobile systems can be shielded with heavy metal cladding that is well grounded . Effectively , the only way to shield against an EMP is to ensure that the inbound energy will take an easy route to ground before striking the system to be protected .