Help converting 6v dc to 6v ac
I am trying to figure out how to convert a small current, say a 1 amp 6v battery, into 6v ac power. I have a bizarre lamp that runs off a power adapter. I want to power it by battery, not by wall-wart. Can you help me with a simple circuit (I'm quite a nube so the more specific the better) or even a lead on a supplier?
Many thanks!