A charging AC adaptor includes: a first diode bridge connected to an AC terminal; a chopper controller connected to the first diode bridge; an insulating air core transformer connected to the chopper controller; a second diode bridge connected to a secondary side of the insulating air core transformer; a DC output terminal connected to the second diode bridge; and a common connection cable connected to the DC output terminal. The charging AC adaptor is connectable to a portable device via the common connection cable.
