Thomas Edison’s dominance in the electric power industry was struck a serious blow when his competitors, Nikola Tesla and George Westinghouse, began to use transformers with their alternating current (AC) electric power systems. Edison was unable to use transformers in his direct current (DC) electric power systems because

It may seem strange that the selected velocity does not depend on either the mass or the charge of the particle. (for example, would the velocity of a neutral particle be selected by passage through this device? ) the explanation of this is that the mass and the charge control the resolution of the device--particles with the wrong velocity will be accelerated away from the straight line and will not pass through the exit slit. if the acceleration depends strongly on the velocity, then particles with just slightly wrong velocities will feel a substantial transverse acceleration and will not exit the selector. because the acc