Below is a rich resource for those wanting more information about EMP. You'll find the entire manuscript of Dr. Peter Vincent Pry's testimony before the House Committee on Homeland Security, including:

Dr. Pry's advocacy for proposed legislation to harden our infrastructureA version of which passed the Senate in December 2016A thorough primer on EMPNuclear, Natural, and Non-Nuclear EMPAn explanation of how EMP would create mass casualties

In the interest of full disclosure, I should also state...