Why do circuits mostly run on a DC current? I understand that electric motors use AC but things like my laptop operate on DC.
Are there another advantages to AC current that made it the standard besides the big one, that voltage can be more easily changed?
Thanks
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.
I understand that electric motors use AC but things like my laptop operate on DC.
There are also DC motors, the motors in your car and in Drones are DC motors.
I could also say that your laptop runs on AC as the power adapter that came with the laptop runs from the mains voltage which is AC.
In general electronic devices run on (low voltage) DC. So your laptop essentially runs on DC, either from the battery (which is always DC) or the power adapter (which converts mains AC into low voltage DC).
For (mains) power distribution AC is more efficient as AC can (more easily than DC) be transformed up to a higher voltage to make long-distance transport of power more efficient.
For transporting power over cables submerged in the sea, DC is more efficient so there high-voltage DC is used dispite the higher costs (compared to AC) to make the high voltage.
So in conclusion, AC and DC are both used. It depends on the application which of the two is more efficient and what is used.
