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

Seb Francis seb at burnit.co.uk
Mon Sep 3 23:35:04 CEST 2007

Hi Dave,

Dave Magnuson wrote:
> with the 555 timer you can get a triangle-like wave from the timing 
> cap. I've seen an LFO that did this with an opamp buffer... it would 
> probably be a little more friendly than the square wave output.

Yeah I thought about this, but I need 20VA output power so no chance to 
get that from an opamp.  I was also thinking I could buffer the square 
wave output from a 555 with a transistor then pass through a simple RC 
low pass filter (with small R and big C) to get a more rounded wave, but 
in the end this isn't going to give me AC, just varying DC.

I also looked at using some switch mode PSU IC like the SG3525 but they 
seem to operate at too high frequencies.

This is the most hopeful thing I've come across:
Looks like it could be used with a 1:1 transformer to give 12VAC out, 
but not sure how it will behave driving an inductive load like a motor...


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