[sdiy] 12VDC to 12VAC converter [OT]

[Seb Francis]

Hi,

Apologies for this OT post but hopefully someone on the list can save me 
a lot of searching ...

I need to produce a 12VAC 20VA 50Hz supply from a 12VDC input.  It's to 
run a 12VAC motor from a car battery, so the AC voltage doesn't have to 
be particularly sine-like or regulated.

Any ideas of a simple circuit or IC that will do this with reasonable 
efficiency?  I thought about a 555 timer with power transistor to boost 
the output but not sure a square wave will be good for the motor ...

TIA,
Seb