west said:

I have an inverter that puts out a nice 120v square wave. The inverters

that

put out a pure sine wave are expensive. Does anyone know where I can

obtain

schematics to build a square to sine wave converter fo my inverter?

If you have a somewhat fixed load at lowish (<100W or so) power levels, you

can use a rather large inductor and capacitor to build a low-pass filter and

knock down the non-60Hz (or 50Hz) harmonics. Add more inductors and

capacitors to make the result as sine-ish as you're willing to pay for...

In the general case of high power/widely varying loads, this approach

quickly becomes more expensive than just buying a sine wave converter in the

first place and hence isn't practical... unless you're looking for an

educational in winding your own high power inductors, which actually is

rather fun...