gulson, No I dont want to go from 12VDC to 12VAC... I want to go from 12VDC -> 24VDC to be able to feed inverters I already have that is 24VDC->240VAC.
The reason that I want to use the inverters that I have, is that those generate high quality true sinus output , compared to the squarewave output that is generated by the example you had.
There is easy to find schematics for Inverters that generate squere, but no that easy to find reasonable simple examples that generate sinus output. And since the Inverters I have is of good quality (I took them from old UPS's) I rather prefer to use them.
/Froggy