Recent Posts

1

Programming / Re: Linux Dependency Black Hole

« Last post by Siwastaja on Today at 05:06:27 pm »

Because their QA team tested it with this version of Python. And their support teams are ready to assist with this version of Python.

Yes. Using Python in the first place is usually a mistake, although no one got fired by using Python, so I guess it's used because it's popular. The problem with Python that fanboys fail to accept but which in actual reality hits nearly every project is that each version of Python breaks compatibility both backwards and forwards (you might not always notice if the project is very simple and thus not using many of the features, but something breaks every freaking time). It's not just Python2 vs. Python3, but really a moving target. You either target one exact Python version and require user to have that exact version, or you maintain your code all day long to match the newest version, and require user to keep updating their Python to the newest release as well. Or you use something as horrible as docker to distribute your software plus the correct Python version.

PSA to all who want to develop software:
 * Do not use bullcrap like Python or docker
 * Avoid dynamic linking, link statically if possible, and therefore:
 * Avoid library dependencies like plague;
 * Only use libraries to do very complex things, like OpenGL for 3D graphics

The danger of "just using a library" to do something as simple as formatting and sending a certain packet was demonstrated on the xz backdoor disaster.

2

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by wraper on Today at 05:05:18 pm »

Here is the UFG series tagline: "Rich sound in the bass register and clearer high end, most suited for AV equipment."

The best part in these is to write some vague fluff yet provide zero measurable specification difference compared to "usual" capacitors.

3

Test Equipment / Re: UTG932 testing by multiple instruments with a lot of screenshots

« Last post by bb1 on Today at 05:03:35 pm »

PDF

4

Test Equipment / Re: MSO2000 Application module hack

« Last post by Minsoon on Today at 05:03:05 pm »

Hi.~
I purchased mso2014 used only yesterday.
There is no logic probe option, so I plan to create this using artwork.
I received good help from eevblog about the Agilent 54831 hack before.
As expected, mso2014 information is also available here.
I upgraded to the latest version 1.56 today.

The serial port on the rear Side will also need to be made using a PCB.
Can I ask for the patched firmware for App-Module Hack?
thank you!.

5

Repair / Re: Desoldering advice

« Last post by KrudyZ on Today at 05:00:43 pm »

I don't get why you are trying to save the relay.
You can certainly test its function while soldered in place.
If it tests good, then it's not your problem.
If it's bad then just get it out by all means, the easiest is to deconstruct (destroy) it from the top by sawing grinding snipping whatever works.
Then you can work on each solder joint separately, which should be trivial.

6

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by shapirus on Today at 05:00:33 pm »

I'd love to play, but I don't have one of these scopes. I have an SDS2504X+ 500MHz scope.

Well, it would still be an interesting data point. What's the lowest samples/sec rate it can do? The idea is to set it to the lowest sampling rate and connect it to a source that outputs a frequency sweep in the range from ~20% to ~60% of the sampling rate.

We can then speculate if the Siglent's 800 HD series have the same wave reconstruction implementation as yours, or not :).

I can sweep up to 841MHz on my scope with the TinySA Ultra.

It can actually output up to 5.4 GHz (or at least so the specs say), but it switches from sine to square wave above 800 MHz.

7

Beginners / Re: Resistor ????

« Last post by Ian.M on Today at 04:59:35 pm »

blk-grey-blk-blk?

180?

The value wouldn't start with black unless the multiplier band was silver, and 180 would be BROWN grey black black.  The grey/silver band has a sheen to it that differs from the pigment bands so is probably metallic silver rather than grey.   Perhaps this color-balanced zoomed in view of it will help.

Its a tossup between:
   Brown (1) Black (0)  Black(0) Silver (/100) Black () = One ohm, with a mystery black final band (as black isn't a tolerance color)
and:
   Brown (1) Black (0)  Black(x1) Silver (10% Tol.) Black (250ppm TC) = Ten ohms, 10% tolerance 250ppm temperature coefficient.

 

8

Test Equipment / UTG932 testing by multiple instruments with a lot of screenshots

« Last post by bb1 on Today at 04:58:03 pm »

UTG932 is popular 30 MHz waveform generator and 100 MHz frequency counter.
The attached PDF describes test results for output frequencies up to 90 MHz and the input frequencies up to 185 MHz,
as well as some glitches.

9

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by KungFuJosh on Today at 04:48:54 pm »

@KungFuJosh can you please set the scope to 500 Msa/s, low waveform acquisition rate (to make the TinySA's glitches less visible), low persistence, and record a video of a 30 seconds long frequency sweep from, say, 110 MHz to 270 MHz?

Coax connection with a 50 Ohm feed-through terminator, if possible, to make the test conditions the same as in my test.

It will be interesting to see at what frequencies (and at what ratio relative to the sampling rate) it will become first wobbly and then AM-like (if it will), to compare that to Rigol.

I'd love to play, but I don't have one of these scopes. I have an SDS2504X+ 500MHz scope. I can sweep up to 841MHz on my scope with the TinySA Ultra.

10

Test Equipment / Second bench PSU, am I thinking about this correctly?

« Last post by krby on Today at 04:47:08 pm »

I am very much an amateur electronics person, with a bit of G.A.S. I'm posting here to get opinions on my approach to buying another PSU.

I've got a 6+ years old Eventek 30V/10A PSU. I've used it for a variety of things, from powering RPis, Arduinos, other small circuits to testing strings of 12 or 24V LEDs, a stand in for 2S to 4S LiPo battery, a crude charger for a variety of battery chemistries, whatever. I don't often need beyond 3 or 5A, but have sometimes. I generally haven't been using it in places where the ripple (IIRC, somewhere around 200mV) mattered or I wasn't sophisticated enough to know it mattered.

Recently, I've been thinking about and doing more projects that I think will benefit from a better bench supply. My thinking is I would keep my existing PSU for anything that really needed >5A because I can't imagine a project I would do in the next few years that needed >5A and needed the accuracy and low noise. I'm also had a few I wanted 48VDC and just used a fixed swithing PSU (meanwell) I already have for another project, but would be nice to have this on the bench supply.

So, all this leads me to thinking about not-expensibe linear supplies that can do about 60V and 5A. This could be a one channel device, or multi channel 30V/5A that could do parallel/series across channels. I get a multichannel w/paralleling PSU, I guess I could ditch the current Eventek because that would be 30V/10A with cleaner output.

Since I'm not willing to spend a ton on this, it has me looking at the "best of the cheap" or "bottom of the quality" end of things. The usual suspects. Keep in mind I've been ok with 200mV ripple now. When I have need accurate voltage, I have verified it with a known good DMM and adjusted the supply until my DMM hit the number I wanted. So maybe the new PSU having voltage sense and feedback would be good?

- Siglent/Rigol The DP832 being the common one I see recommended here
- Korad KA3005 or KA3305 for multi output.
- Maybe super cheap RD6012P (it looks like in the 0-6A range it acts just like a 6006P) ? Should I even bother with  these sort of "20mV ripple SMPS" things or just go linear?

I'm not sure I'd actually use the multiple channels all that much. But maybe that's just because I don't have them now.
Is there anything else I should be considering? I don't know if I need memory slots, I'd use them for some common configs I guess, but not required. Since I'm upgrading I would like to be able to have some better input than just coarse/fine pots. But I guess that's not required if it saves a ton of money. I haven't looked deeply at what the computer interfaces do with these things, generally I'd say I would do without that. I haven't come up with complex control needs, mostly "set to a given max current, get the voltage I want, go". Then maybe "vary current and voltage a bit manually" if I need to see how things behave.

Thanks for any advice.