The Vacuum Tube's Forgotten Rival: Magnetic Amplifiers, the Alt-Tech of the Third Reich, Lasted into the Internet Era

During the second world War, the German military developed what were at the time some very sophisticated technologies, including the V-2 rockets it used to rain destruction on London. Yet the V-2, along with much other German military hardware, depended on an obscure and seemingly antiquated component you've probably never heard of, something called the magnetic amplifier or mag amp.