Anyone here experienced in reading oscilloscope sine waves?

[Gazoo]

A scope with storage would show only one trace. Since there is a 20KHZ or so signal imposed on the sine wave, you see a double trace. Some scopes have a TV filter. If you looked at the waveform thru a transformer it would probably filter that out. As with any piece of test equipment, you should never trust what you see.

So would that explain why the sine wave in the attached photo is clean? This is the sine wave from same inverter with no load on it.

 

[OnTheRoadAgain]

So would that explain why the sine wave in the attached photo is clean? This is the sine wave from same inverter with no load on it.

But when I connect the Inverter that I have to the scope and the one I had, the sine wave is clean until I switch it on.

As long as the switch is off I get a clean sine wave. I shouldn't even get a sine wave at the outlets when it's off.

 

[svetz]

Is there a forum for your oscilloscope or scopes in general? Probably more experts there, but if you find out please post here.

 

[wholybee]

I don't think there is anything "wrong" with the inverter, just that it may be of a low quality. The 2 waveforms are in phase, the same amplitude, but have a small dc shift. Could be a poor ground to the inverter. It could be poor filtering or a low quality clamping circuit in the inverter. Note that some inverters connect ground and neutral internally, some leave them separate, and some will connect while on but disconnect while running. How the inverter is handling that could be part of the odd results.
But I would hesitate to say it's broken.

 

[Zwy]

Don't most oscilloscopes have a way of filtering that? Or limiting the range?

Some do, if you had a DSO like I use, you can add filter, peak detect. One thing you need to understand is sampling rate and the resultant aliasing that can occur. Always use the shortest time division you can to limit aliasing. That is difficult when not using a DSO. I always use the shortest sweep I can, then stop sampling and zoom out.

Good quality DSO's like the Pico or a used Snap On DSO can be purchased used very reasonable. I own 4 DSO's, you can't have too many.

 

[OnTheRoadAgain]

Some do, if you had a DSO like I use, you can add filter, peak detect. One thing you need to understand is sampling rate and the resultant aliasing that can occur. Always use the shortest time division you can to limit aliasing. That is difficult when not using a DSO. I always use the shortest sweep I can, then stop sampling and zoom out.

Good quality DSO's like the Pico or a used Snap On DSO can be purchased used very reasonable. I own 4 DSO's, you can't have too many.

Is an Hitachi 1050F a DSO scope? If the 'D" stands for "Digital" then I alrady have my answer. Mine is an older, analog Hitachi

 

[Zwy]

Is an Hitachi 1050F a DSO scope? If the 'D" stands for "Digital" then I alrady have my answer. Mine is an older, analog Hitachi

Doesn't appear to be, it's an analog. D stands for digital, S for storage so you can review the data, even measure peak to peak V or time.

 

[GSXR1000]

So, I got the 2nd one from Amazon today.
Hooked it all up and connected the Oscilloscope to it.

EXACT same results.
I tested this one with a load. 499watts for 10 minutes no problem.
520watts for 1 minute, no problem.

I've contacted Bestek for information regarding the unusual Sine wave.

Meanwhile, I'm going to keep the 2nd one and take my chances.

I could not even get a definitive answer at forums that specialize in electronics. So maybe it's some kind of electronic wizardry to get the "improved" sine wave from it. I would not call it a 'Pure Sine wave" inverter. But perhaps "a good bit better than a Modified Sine Wave" inverter.
Time will tell.

This one goes in the car and is used when traveling for various things so it won't see full time or heavy duty.

View attachment 45032

if underload it is fine... but does that in no load it could be a power saving feature ?

 

[OnTheRoadAgain]

I just wne to YT hoping to look at a few more Bestek 500watt reviews (REAL ones)

YouTube has become a dumping ground for Affiliate Junkies hoping to score a bit of pocket change if you click their link.
It's really ruining the place because you have to wade through 10 affiliate link Click Bait videos to get to one that has real content.

Just me, but I think YouTube has gone to hell ever since Google bought it.

ALL they care about is revenue and more revenue. The exact same mentality killed MySpace.
Excessive, overbearing, unending, disgusting mega commercialization. They already have enough money to buy the world 1000 times over.

I hope a viable alternative pops up very soon. Im ready to leave YT