[HomeBrew] Smoothing a square wave

[wabate]

Jim,

I am tackling the same problem except for a generator.  You would think 
that a generator would have a smooth sine wave.  No so.  I have not been 
able to find anything on smoothing out the wave form.  Mine is not as 
bad as yours.  It just has 'grass' on the sine wave.  But I don't want 
to repeat your experience.

I also have a UPS but the output is fairly clean.  It is a higher priced 
UPS by Lierbert.  That said, I would not use the pole pig.  If the 
primary is 220 volts, the impedance is way too high.  Besides a pole pig 
with a HV secondary is dangerous.  I would suggest a 120v/120v 
transformer to smooth things out.  Maybe a cap on the secondary?   You 
will have to experiment.

Bill, K3PGB

Jim Miller wrote:

>** Please do NOT cross-post messages when posting to HOMEBREW **
>
>I have an inverter that I blame for blowing up a 9 inch color TV that I use at my station and wanted it also to run on 12v as battery backup as my station does.  I scoped the output and it is a two-step (two positive and two negative) square wave output.  I had also  intended to connect my computer to it but haven't tried that because the TV blew up.  Does anyone know what the output of these UPS systems look like?
>
>At 60 Hz, it would take a huge inductor to "round" the corners of the wave but I have a very large pole pig sitting here and wondered if one side could be used simply as an inductor or wire the two sides in series, maybe put a load on the unused side or something.  High side or low side?  How much of a load?  Use a cap instead of a load?  OK, dumb idea.
>
>For a small TV only maybe a small LONG "extension" cord wound in a small coil would help smooth the square wave?
>
>1. It says the max current is 1 amp.
>2. 20 gauge (too much voltage drop?  I don't have the numbers to calculate it.
>3. 100-200 feet?  Not long enough to create enough inductance?  
>
>Opinions please, I am not a design engineer, just trying to get a small TV to safely run on an inverter or was it coincidence that it quit within minutes of plugging it into the inverter?
>
>Thanks es 73 de Jim KG0KP
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