Recent Posts

1

Test Equipment / Re: Siglent SDS1000X HD 12bit DSO's

« Last post by BillyO on Today at 12:20:11 pm »

That was pretty lightweight for a Dave dive.

Hope he does more when he comes to the DSO800X-HD.

2

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by tooki on Today at 12:20:07 pm »

Your reasoning is detached from the outcome.

That’s a rather lofty accusation.

I worked in the software industry for years, and at a usability agency. I have relevant, real-world experience with this, and am not the deluded simpleton you essentially accuse me of being.

Yes crash reports and usability reports are good data sources.

Do they benefit the user? That depends on the sausage factory in the middle of the process.

Sure, that’s fair.

I have never seen an outcome that is user beneficial from a usability study.

Hold on, we aren’t talking about usability studies. We are talking about usage data, which is used to inform subsequent usability design.

I literally gave a real-world example: the post-pasting popup menu in Microsoft software (Office, etc). Usage telemetry had shown that the “paste” command is very frequently followed by “undo”, because the result was not as intended. Then people would either use a Paste Special command, or paste it normally and follow it by manual reformatting. So they added the little popup that lets you change the pasted formatting in situ. I think this is a fantastic feature, and well-implemented: it makes it easy to recover from an unexpected result, yet doesn’t force any change to one’s workflow at all: you can also simply ignore it and fix the problem in the old ways.

I posit that they are run by people who have no idea what they are doing.

Every industry and specialty has people who are incompetent and people who are competent. You can’t just dismiss all usability research as “run by people with no idea what they’re doing”.

As for the other point, my day job for the last couple of years has been running the reliability engineering team for a very large fintech. If you think that a crash dump results in a viable outcome for end users even 5% of the time then you are naive. Most of the time it is just noise. We get thousands of them an hour. And that is considered normal. Even if we do perform a causal analysis on a statistically common one, finding an engineer who can actually understand or solve the problem in a complex distributed system is an uphill battle as well.

The ratio depends entirely on the product, of course. At the small software company I worked at, where the software could generate a crash report as a precomposed email (user still had to actively send it), the trace went straight to the dev team, which knew exactly what it meant and could take action if necessary.

I don’t doubt for a second that in complex, larger systems the ratio of useful reports is smaller. But if you ask me, even if just 5% result in a bug being fixed, that is a good thing. I fail to see how it’s better than nothing.

The general theme in the thread above is there aren't a lot of people who know what they are doing. They are all making appropriate looking dances though and people who don't know what they are doing look at those and think they might know what they are doing. It's not turtles, but incompetence from the top to the bottom.

And that's why we shouldn't trust, not because the idea is bad, but the competence is bad.

I don’t disagree in principle with that statement, but maybe I’m just not quite as jaded as you.

3

Beginners / Re: Automatic golf ball dispenser

« Last post by BTO on Today at 12:18:36 pm »

The reason why I want to move away from the leaver is that it moves the bucket. Gradually over time which means it loses alignment with the tee.

And I hate it when people come in and propose a microcontroller for something which very clearly does not require a microcontroller

LOL...

1. don't HATE, Never hate, it's a bad habit.
One thing i've learned in 50 years is we have so many people in this world and they all have many different personalities and each
have their own psychologies that are associated with them. As humans we can only get along with people who have the same or similar
psychologies as our own, which ultimately means you cannot get along with everyone.. EVER !!!

that being the case, If you hate because someone did something that you didn't agree with (According to your psychology) then you are fighting a losing battle my friend and will do nothing but frustrate yourself and cause yourself health issues later in life.

2. But did it ever occur to you that there were other reasons why people suggest he use a micro ?
YOU ARE CORRECT... It's not necessary. But this person came to us with a very simple problem, but a problem that wasn't simple for him.
as tech people we want to help him AND GIVE HIM IDEAS and even though not necessary now, the introduction
of a dev board now is going to lead him down different paths of possibility that will either help him solve his problem or cause him to think in different directions and help him down the track, or perhaps he has this underlying idea that he didn't bother to mention that does actually require a dev board but now that it was mentioned, becomes a possibility

Mate, it's called  BRAIN STORMING,  it doesn't have to make sense or be necessary at first.
and if he's never used an arduino, and given his curiosity  HE SHOULD LEARN HOW TO USE ONE

Just like a person who has never used a hammer should go out and find nails to pound into timber if for nothing else but the experience.
This project may start as an arduino project, then he'll encounter issues on V 1.0 , then he'll refine it and perhaps on v 6.0 it turns out being
what you said and has nothing to do with arduino.. BUT HE GAINED EXPERIENCE FROM IT that would help him in later projects.

Never hate, it's not productive to anyone

4

Beginners / Re: Blocking Phantom Power 48V from Audio output

« Last post by BennoG on Today at 12:15:39 pm »

yes you can, I would also add a extra resistor of 100k or 220k to the ground after that to discharge the capacitor.

However you need to double the capacity of the 22uF to 47uF or something like that, because capacitors in series act the same as resistors in parallel.

Benno

5

Buy/Sell/Wanted / Re: FS: Affordable DMM Checkers: AC Reference, DC Reference, OHMS Reference, etc.

« Last post by tggzzz on Today at 12:13:37 pm »

If you limited the claimed to, for example, "...verify the function of 3.5 digit Digital Multimeters", then the points wouldn't even arise.

What you claim here (or "elsewhere") is irrelevant; what you claim in the advert is what matters.

This is basic measurement theory. While you need higher resolution than the manufactured reference to measure its calibration error, that same calibration reference can then be used on on lower resolution instruments (assuming it is stable).  If you only work in mA, you do not care what is going in pA.

So a lot depends on claims for where it should be used.  And the reliablity of the maker.

FWIW, I bought one of the current and voltage references from AliExpress.  It includes a sketchy paper claiming the actual values as measured by some reference down to the 7th decimal point.  Turns out these measurements were within a couple counts on my Fluke 45, Fluke 8842, HP 358a and Keysight 1252.

Have no idea why I bought it since all my instruments already agreed, but it was cheap and I am a measurement junkie (work down to 500 micro meters).

Yes, repeatedly.

You bought it for fun. The only surprise is the degree of agreement.

But, as you know, it is relatively cheap and easy to get all your instruments to agree with each other. It is much more difficult and expensive to get them to agree with two other people's instruments

6

Test Equipment / Re: New Zoyi multimeter+oscilloscopes - ZT-70xS, up to 50MHz/250MSps (nov 2022)

« Last post by lazalem on Today at 12:12:44 pm »

Good Day!

Just want to know if ZT-703S is a good multimeter+oscilloscope for a hobbyist like me.  I am coming from a DSO150.  Which is a better buy among these:

Zoyi ZT-703S ~ 37.80USD (New)
Owon HDS242S ~ 74.16USD (New)
Owon HDS2202S ~ 78.07USD (Used)

At double the price, does the owon variants have better features, accuracy, reliability?


Thanks!

7

Repair / Re: Rigol DP712 Output Shorted; Fuse? / I Screwed Up

« Last post by Harry_22 on Today at 12:06:36 pm »

Dear Zanfar, unfortunately your power supply does not allow the direct battery connection.
No one could have foreseen this.
The fact is that the capacitor is installed at output. It is discharged through thyristor when the voltage is removed by pressing on/off button. When you connected the battery you voltage obviously was off and current passed through the thyristor. The swelling of thyristor case shows that the current was very large.
This can be corrected by installing an external diode between PS and battery (see scheme below).
I can't understand only the function of p-channel MOSFET.

8

Beginners / Re: Automatic golf ball dispenser

« Last post by BTO on Today at 12:05:33 pm »

Hay guys, sorry it took so long to respond, I went out to get some parts.

What there is left to right

Battery pack
Something that I don’t know
Relay switch
A timer
A vibration switch
Solenoid
And an arduino uno
Plus plenty of bits

I think I have enough to create something. But as mentioned about I want the vibration switch to trigger the solenoid. I’d like connect this to the T so that when I swing at the ball it triggers a new ball to load.

The thing that YOU DON'T KNOW is an "MB102"  POWER INTERFACE MODULE.
Basically i'ts a regulated power supply for your breadboard.
Plut it into your breadboard and it'll stretch from one side to the other all the way.

it has 2 channels so it has the ability to provide one power rail side of your breadboard with a certain voltage
and the ability to provide the other power rail side of the breadboard with the same voltage or another voltage

the way it works is... You'll input , via the jack 6.5V to 12V, most use a 9V Battery here
and it supports a regulated 3.3V or   5V on the output, and the USB can also be used as an output

so yeah.. it's a power supply

9

Projects, Designs, and Technical Stuff / Re: role of optocoupler for biasing drain of amplifiers

« Last post by xvr on Today at 12:04:42 pm »

Your overall schematic is very over-complicated. You need just P channel MOSFET, one NPN bipolar transistor and a couple of resistors.
I will draw schematic...

All resistors values are taken approximately.

Q1 - your power MOSFET. Should have DrainToSource breakdown voltage > 20V. GateToSource also >20V. RDSon will determine voltage drop and power dissipation on MOSFET.
Q2 - any NPN transistor with CE > 20V and high enough Ic (100mA or more will be enough) - it will define turn on time of schematic. R2 limit Ic of Q2.
R1 used to discharge Q1 Gate, it will determine turn off time.
R3 determine Ib of Q2. Should be low enough to ensure Ic (with minimum h21e of Q2

10

Programming / Re: Linux Dependency Black Hole

« Last post by xvr on Today at 12:02:49 pm »

It is 28 of .c and .h files. I wanted to put breakpoints to trace through the math which is meandering  over at least 3 of the .c
And the headers are all mixed up hard for me to follow I think due to multiple versions over 10 years.
Can all that be done in eclipse and gdb?

Yes, absolutely.

Eclipse is an IDE that use gdb for debugging, so you need to deal with gdb only.

First of all you need to build project. What build system is used in it? Can you see any of these files at top level?

Makefile
configure
CMakeLists.txt