13 Feb 2017 16:14
The electrics system can be split into two parts - AC and DC.
AC is generated by the two engine generators, an APU generator and ground power. DC is generated by the batteries.
Each part can also generate power for the other. The AC system can generate DC power using a TR and the DC system can generate AC power using a static inverter.
There's a great schematic diagram in the FCOM which helps simplify the system.