[Arm-netbook] Oscilloscope or bust?

[David Niklas]

Hi,
I need help here. I was designing the power supply of my laptop and I
noticed that some power bucks and step up/down converters (Which both
seem to do the same thing. Please tell me otherwise.), produced a more
stable power supply than others. In order to find out if they are truly
suitable for suppling power to sensitive electronics I've heard that I
need an oscilloscope.
I currently own:

1. #222634543946
"DC-DC 10/12/15/20A 150/250/300/400/1200W Step up Step
down Buck Boost Converter"

2. #152710861245
"2A DC Boost Step-up Adjustable Converter Module 3v-24v to 3.3v 5v 6v
9v 12v 24v"

After learning that some guy with an oscilloscope reviewed these, I'm
planning to get: #122923215542
"6 Pack MP1584EN ultra Small DC-DC 3A power Step-Down
Adjustable Module Buck M2H3 6 Pack MP1584EN ultra Small DC-DC 3A power
Step-Down Adjustable Module Buck"

I've seen many oscilloscopes online on crowd funding campaigns. I've
never been certain of which to get, if any. The real professional ones
are out of my budget range of about $100. *I'll pay more if I must*, but I
already did not anticipate the need to actually evaluate what should be
solid products.
I probably should find a solid adjustable DC power supply to test these
with vs. an old laptop power pack or some batteries.
What I need some of these things to do is to take a dynamically variable
voltage as input (Li-Ion batteries in series), and produce a constant
voltage as output. Others I need to just convert to the correct voltage
from the old laptop power pack.

Thanks!
David

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arm-netbook mailing list arm-***@lists.phcomp.co.uk
http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook
S

[Christopher Havel]

Pardon a top post, plz, I'm on my phone again...

Oscilloscopes are a great tool for either (a) analyzing analog waveforms,
if you know what you're doing, or (b) looking like the absolute incarnation
of technological tomfoolery, if you don't.

Mostly I fall into the second category. My scope is a secondhand,
pre-moonshot Tektronix 422. It weighs about as much as a good stout WW2
battleship and probably has just as much metal... it certainly has almost
as many controls, and the dizzying array of knob and levers and buttons
means I have virtually no idea how to work it. I do have the manual and a
lot of bad excuses, though!

...anyways...

These links may be of some use. The first couple are a little outdated, but
all should be serviceable...

https://hackaday.com/2016/01/27/a-tale-of-two-sub-100-oscilloscopes/

https://hackaday.com/2017/11/09/review-jye-tech-dso150-oscilloscope-kit/

https://hackaday.com/2017/11/18/ds212-oscilloscope-review-open-source-and-great-for-hacking/

...and, if you're "Robinson Crusoe on a Desert Island" desperate (note, I
wouldn't trust myself with this one!)...

https://hackaday.com/2017/04/06/hacking-a-vintage-tv-into-an-oscilloscope/

There are also dead-simple recipes out there (Forrest Mims, /et al/) for
o-scope builds using (literally) a few chips and a double-fistful of
LEDs... but those badly lack the sort of display resolution you need for
this.

HTH...

Chris

Post by David Niklas
Hi,
I need help here. I was designing the power supply of my laptop and I
noticed that some power bucks and step up/down converters (Which both
seem to do the same thing. Please tell me otherwise.), produced a more
stable power supply than others. In order to find out if they are truly
suitable for suppling power to sensitive electronics I've heard that I
need an oscilloscope.
1. #222634543946
"DC-DC 10/12/15/20A 150/250/300/400/1200W Step up Step
down Buck Boost Converter"
2. #152710861245
"2A DC Boost Step-up Adjustable Converter Module 3v-24v to 3.3v 5v 6v
9v 12v 24v"
After learning that some guy with an oscilloscope reviewed these, I'm
planning to get: #122923215542
"6 Pack MP1584EN ultra Small DC-DC 3A power Step-Down
Adjustable Module Buck M2H3 6 Pack MP1584EN ultra Small DC-DC 3A power
Step-Down Adjustable Module Buck"
I've seen many oscilloscopes online on crowd funding campaigns. I've
never been certain of which to get, if any. The real professional ones
are out of my budget range of about $100. *I'll pay more if I must*, but I
already did not anticipate the need to actually evaluate what should be
solid products.
I probably should find a solid adjustable DC power supply to test these
with vs. an old laptop power pack or some batteries.
What I need some of these things to do is to take a dynamically variable
voltage as input (Li-Ion batteries in series), and produce a constant
voltage as output. Others I need to just convert to the correct voltage
from the old laptop power pack.
Thanks!
David
_______________________________________________
http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook

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Post by David Niklas
I've seen many oscilloscopes online on crowd funding campaigns. I've
never been certain of which to get, if any. The real professional ones
are out of my budget range of about $100. *I'll pay more if I must*, but I
already did not anticipate the need to actually evaluate what should be
solid products.

If you want to, write to me privately and give me an idea of where you live --
I have an old osciloscope (in a closet that is hard to access ;-) that I'd
probably be willing to sell at a reasonable price.

I can't remember the brand offhand, it is approximately 40 years old, I never
used it hard, and the original cost was over $1000 (I bought it new). I'm
sure the bandwidth is at least 20 MHz., and may be higher. (I just don't
remember -- I know I wanted to find something that would be suitable for the
clock speed of the Digital Group computer I was building (from a kit).)

Reasonable price -- well, I'm thinking about that. I used it to work on my
Digital Group computer kit that had some problems (back around 1977), and
haven't used it since. I sort of like having it sit in the closet in case I
need it (or I get my son interested in something for which he'd use it), but,
if I'm realistic, neither will probably happen.

Hmm, I guess I might be willing to sell the DG computer as well, if anyone is
interested (uses a Z-80 CPU) and has some problems.

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[David Niklas]

On Sun, 9 Sep 2018 23:25:42 -0400

Post by David Niklas
Hi,
I need help here. I was designing the power supply of my laptop and I
noticed that some power bucks and step up/down converters (Which both
seem to do the same thing. Please tell me otherwise.), produced a more
stable power supply than others. In order to find out if they are truly
suitable for suppling power to sensitive electronics I've heard that I
need an oscilloscope.
1. #222634543946
"DC-DC 10/12/15/20A 150/250/300/400/1200W Step up Step
down Buck Boost Converter"
2. #152710861245
"2A DC Boost Step-up Adjustable Converter Module 3v-24v to 3.3v 5v 6v
9v 12v 24v"
After learning that some guy with an oscilloscope reviewed these, I'm
planning to get: #122923215542
"6 Pack MP1584EN ultra Small DC-DC 3A power Step-Down
Adjustable Module Buck M2H3 6 Pack MP1584EN ultra Small DC-DC 3A power
Step-Down Adjustable Module Buck"
I've seen many oscilloscopes online on crowd funding campaigns. I've
never been certain of which to get, if any. The real professional ones
are out of my budget range of about $100. *I'll pay more if I must*,
but I already did not anticipate the need to actually evaluate what
should be solid products.
I probably should find a solid adjustable DC power supply to test these
with vs. an old laptop power pack or some batteries.
What I need some of these things to do is to take a dynamically variable
voltage as input (Li-Ion batteries in series), and produce a constant
voltage as output. Others I need to just convert to the correct voltage
from the old laptop power pack.
Thanks!
David

Alternatively, does anyone know a good place to ask?

I searched a lot online and found a forum www.electro-tech-online.com
which I signed up to and was rejected. It was a very weird sign up
process. You're supposed to input your name but the form will only take
one character (and allows white space as that one!) You also have to tell
what education level you're at (I choose student), and what your
expertise is, which being a student was none, but they did not have that
choice and the others were things like "PCB layout engineer," so I
selected everything.
After being rejected I wrote to the admin asking the reason and have yet
to get a response after about a week...
In other news, I found a couple of guys on youtube who did a review of
the 300W buck converter I own and it seems to be a good model with a
168mhz switching freq and 218ma voltage variation independent of load, but
I must confess that I have not done any work with computer circuits until
now so they might have stricter requirements than I think.
So, I think I'll add a 3.3uf capacitor onto the leads and call it quits
from there. 3.3uf should be able to reach saturation at 168mhz unless my
calculations of the time constants are incorrect. Feel free to check me
on that, I did use a calculator this time (I learned via pencil and
paper and I still have my notes!)

Still, I think I could use a good place to ask these questions on because
although this list is called "arm netbook" it seems that a lot of
questions I post on the subject go unanswered, but that might just be my
perception :)

Status update: other than the above, I'm still trying to find genuine
Li-Ion batteries (both my stock of Li-Ion and my Ni-Mh batteries are
duds. I did replace the Ni-Mh ones), and I managed to fry a pair of my
tester leads (turns out that the tester is rated for 10A and the leads
for 8A? So I'm building an open source set of leads. :) They "mind
melded" to each other when I decided to test if my 300W buck converter
would work.
Another annoying thing is that it turns out that electrolytic capacitors
are being faked in addition to batteries. I never needed a capacitor
tester before because the ones that were not bulging were marked and the
ones that are bulging are not safe. So I am getting a little TC1
multi-function tester that was reviewed here:
https://lygte-info.dk/review/ComponentTester%20Multifunction%20Tester%20T1%20UK.html
The gentlemen also reviewed a bunch of batteries, but most of them are no
longer available or are very expensive.


Thanks!

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[Christopher Havel]

Sounds like you're taking your plunge at the deep end of the pool, and
you're getting a bit lost along the way because you're in over your head.

Get this book. Read it. Study it. Build things. (Don't trust eBay for
parts! I know this from experience.) You will LEARN.

https://www.amazon.com/dp/0945053282

Alternatively, if you dig around, you may be able to find a PDF copy of
"MAKE: Electronics" online. That would also be a good book to start with.

First learn to swim. Then learn to dive. Then you can truly get out of the
shallows...

Post by David Niklas
On Sun, 9 Sep 2018 23:25:42 -0400

Post by David Niklas
Hi,
I need help here. I was designing the power supply of my laptop and I
noticed that some power bucks and step up/down converters (Which both
seem to do the same thing. Please tell me otherwise.), produced a more
stable power supply than others. In order to find out if they are truly
suitable for suppling power to sensitive electronics I've heard that I
need an oscilloscope.
1. #222634543946
"DC-DC 10/12/15/20A 150/250/300/400/1200W Step up Step
down Buck Boost Converter"
2. #152710861245
"2A DC Boost Step-up Adjustable Converter Module 3v-24v to 3.3v 5v 6v
9v 12v 24v"
After learning that some guy with an oscilloscope reviewed these, I'm
planning to get: #122923215542
"6 Pack MP1584EN ultra Small DC-DC 3A power Step-Down
Adjustable Module Buck M2H3 6 Pack MP1584EN ultra Small DC-DC 3A power
Step-Down Adjustable Module Buck"
I've seen many oscilloscopes online on crowd funding campaigns. I've
never been certain of which to get, if any. The real professional ones
are out of my budget range of about $100. *I'll pay more if I must*,
but I already did not anticipate the need to actually evaluate what
should be solid products.
I probably should find a solid adjustable DC power supply to test these
with vs. an old laptop power pack or some batteries.
What I need some of these things to do is to take a dynamically variable
voltage as input (Li-Ion batteries in series), and produce a constant
voltage as output. Others I need to just convert to the correct voltage
from the old laptop power pack.
Thanks!
David

Alternatively, does anyone know a good place to ask?
I searched a lot online and found a forum www.electro-tech-online.com
which I signed up to and was rejected. It was a very weird sign up
process. You're supposed to input your name but the form will only take
one character (and allows white space as that one!) You also have to tell
what education level you're at (I choose student), and what your
expertise is, which being a student was none, but they did not have that
choice and the others were things like "PCB layout engineer," so I
selected everything.
After being rejected I wrote to the admin asking the reason and have yet
to get a response after about a week...
In other news, I found a couple of guys on youtube who did a review of
the 300W buck converter I own and it seems to be a good model with a
168mhz switching freq and 218ma voltage variation independent of load, but
I must confess that I have not done any work with computer circuits until
now so they might have stricter requirements than I think.
So, I think I'll add a 3.3uf capacitor onto the leads and call it quits
from there. 3.3uf should be able to reach saturation at 168mhz unless my
calculations of the time constants are incorrect. Feel free to check me
on that, I did use a calculator this time (I learned via pencil and
paper and I still have my notes!)
Still, I think I could use a good place to ask these questions on because
although this list is called "arm netbook" it seems that a lot of
questions I post on the subject go unanswered, but that might just be my
perception :)
Status update: other than the above, I'm still trying to find genuine
Li-Ion batteries (both my stock of Li-Ion and my Ni-Mh batteries are
duds. I did replace the Ni-Mh ones), and I managed to fry a pair of my
tester leads (turns out that the tester is rated for 10A and the leads
for 8A? So I'm building an open source set of leads. :) They "mind
melded" to each other when I decided to test if my 300W buck converter
would work.
Another annoying thing is that it turns out that electrolytic capacitors
are being faked in addition to batteries. I never needed a capacitor
tester before because the ones that were not bulging were marked and the
ones that are bulging are not safe. So I am getting a little TC1
https://lygte-info.dk/review/ComponentTester%20Multifunction%20Tester%20T1%20UK.html
The gentlemen also reviewed a bunch of batteries, but most of them are no
longer available or are very expensive.
Thanks!
_______________________________________________
http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook

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