Why is DC used in circuit devices?
Why do circuits mostly run on a DC current? I understand that electric motors use AC but things like my laptop operate on DC.


AC voltages passes through zero volts 100 or 120 times a second (depending on supply frequency). The circuits would all shut down at every zero-cross. Everything would become much more complicated. The biggest reason for electronics is that transistors only work with current flowing one way. AC would not work.


  Are there another advantages to AC current that made it the standard besides the big one, that voltage can be more easily changed?


The ability to transform voltages and currents for easy distribution is the main one. Another is that synchronous or near-synchronous motor speed is easily achieved and this gives consistent speed for industrial motors.