First DS1054Z waveform - is this 70 vpp ripple ??

[ez24]

Hi

This is from a small buck module bought on Aliexpress.  It is constant V and I and I took these readings at 3.3 v  0.5 amps.  So far impressive because I can set the max V and the max I.

Do the pictures look like 70 vpp ripple?

ps - this is my first use and waveform from my new Rigol.

thanks

edit: corrected mistakes

[Skimask]

Time to re-read the manual.

[Armxnian]

The 30mv value in the top right is the trigger level.

[Rick Law]

I guess your poor school in the third world find ways to afford it after all...

If you are going to teach concepts, I think you best read the manual beginning to end.  I am a relative newbie myself too.

Looking at your attached photo, it looks like you are on 10mV/division, and the wave spans just about 7 divisions.  So it looks like your wave is around 70mV p2p from what is visible.  This would be about what I expect from my small collection of 5 to 6 buck boards with different architecture.

Rick

Hi
...
I am looking for a scope and here are my specs (lets stay within them):

- Under $100
- Good documentation
- No batteries and no AC  (to be powered by a laptop ps)
- No used equipment

I am looking for a scope that meets the above specs that can be used as a training tool at the high school level in a poor school system (ie one that cannot afford Rigol scopes).  I have looked at many many scopes and maybe there is something better but so far I have not found any with something that is VERY important:
...
Edit - this is to teach concepts

thanks

[ez24]

FYI the Rigol is to test the < $100 scopes.  I got the Xminilab and I am waiting for a DSO112.  Once I get used to the Rigol and get the DSO112, I will start looking at it and the Xminilab using the Rigol to compare them with. The Rigol is for me, the other two are what I am looking at for the "lab".

The first thing I notice is the Rigol is much easier to use, I just plug it in.  I have to read the manual on the Xminilab because I have to figure out how to add power and probes and the controls.

[aveekbh]

...
Do the pictures look like 70 vpp ripple?
...

Hello ez24, do you have a typo there? That's 70 mVpp - channel 1 is set to 10 mV/div.
Also, what is the current being drawn from the buck regulator? Check against the specs (if they are available).

[Rick Law]

FYI the Rigol is to test the < $100 scopes.  I got the Xminilab and I am waiting for a DSO112.  Once I get used to the Rigol and get the DSO112, I will start looking at it and the Xminilab using the Rigol to compare them with. The Rigol is for me, the other two are what I am looking at for the "lab".

The first thing I notice is the Rigol is much easier to use, I just plug it in.  I have to read the manual on the Xminilab because I have to figure out how to add power and probes and the controls.

Ah - good that I did not say congrats.  I thought you managed to get a budget large enough some how.

As to reading the manual and adding power/probes, it is just a one time event.  Best of luck!

[Delta]

Yes, that's seventy volts ripple.

You can always see 70v on a 10mv/div scale...

[continuo]

You just need a bigger screen 

[ez24]

Also, what is the current being drawn from the buck regulator? Check against the specs (if they are available).

Sorry about that - in my first failed attempt to add pics - I had pics of the load = 3.3 v  at 0.5 amp

I am going to start a new topic on just the buck regulators that I got now that I know what ripple and trigger voltages are.  I will add it when I do.   I am running the buck at 2 amps now and will look at the ripple again.