Test Equipment Anonymous (TEA) group therapy thread

[salvagedcircuitry]

Someone, please hold me back from low balling...
Huba huba huba 3458a.
Help me come up with an excuse to why I need all those digits 
https://www.ebay.com/itm/303266627627

[mnementh]

Twell-dolla!!! 

mnem
"oookaaayyy... firteen..."

[Zucca]

Someone, please hold me back from low balling...
Huba huba huba 3458a.
Help me come up with an excuse to why I need all those digits 
https://www.ebay.com/itm/303266627627

30% it's a deal, 70% you will spend a lot of money and time on it.
Summo TiN docet.

Don't forget about him

He is watching you all the time.

[Zucca]

Talking about TiN, in case you missed it:

https://www.eevblog.com/forum/metrology/(post-4000)-si-redefinition-and-my-experience-with-nml-calibration/msg2643585/#msg2643585

 another masterpiece from him.

[bd139]

(Attachment Link)

Here.... this'll fix its arse right up. Might work on those zones as well; it's pretty aggro stuff... 

mnem
" Very helpful.... very helpful indeed." Chibila thought to himself...

 

Delved inside the damn files and deleted the zone by hand. The PAIN hasn't gone yet.

It got so bad I nearly bought Eagle. Then I realised Autodesk own them now so I crawled back to my position of taking it from the open source delegate minor devil rather than satan himself.

[worsthorse]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

[worsthorse]

Talking about TiN, in case you missed it:

https://www.eevblog.com/forum/metrology/(post-4000)-si-redefinition-and-my-experience-with-nml-calibration/msg2643585/#msg2643585

 another masterpiece from him.

Yikes! How does he have time to do anything but post here?

[med6753]

Talking about TiN, in case you missed it:

https://www.eevblog.com/forum/metrology/(post-4000)-si-redefinition-and-my-experience-with-nml-calibration/msg2643585/#msg2643585

 another masterpiece from him.

Yikes! How does he have time to do anything but post here?

Certainly makes my bench references feel totally inadequate......more like impotent. 

[worsthorse]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

you know, if i deleted all the posts that provided evidence of my ignorance, i'd be able to count the ones left on one hand...

i did some more thinking about my question. of course, after i posted it. then i went down to the bench to do a little more experimenting, along with a wee bit of figuring numbers. given the input impedance of the fluke meter, and the fact that it is displaying five point five digits at on the 200 mV scale, that's a 1uV resolution. doesn't take much current across 10 MOhms to change that last digit up or down a couple. should have done the calculation before posting. 

i also realized that i introduced random errors by not being careful with my test setup.  i set everything up again with more attention to detail and found that the fluctuations are a tenth of the size that i thought they were.   

truth is, i am not used to measuring anything down to microvolts or milliohms or nanoamps.  almost everything i designed or built or fixed when i was doing this for a living rarely required better than slide rule precision.  maybe i should just tape over the right side of my meters so they only show two digits after the decimal.   

i am pretty sure that i will never stop feeling, or acting, like an electronics noob. 

so.... nevermind

[mnementh]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

WAG-

PWM noise from nearby LED lighting or some device with PWM-controlled LED backlighting. Actually, nowadays, that's my FIRST guess anytime I see any weird "noise" type issue, as it has been proven right as a WAG so many times it's scary.  Closely followed by nearby WiFi/BT signal sources. Had to get rid of a favorite BT mouse/KB because it was effing noisy as hell. Okay, I gave it to my wife as her laptop is usually at the other end of the house.

That said... you are aware that these high-impedance, high-digit meters are generally a lot more sensitive to noise than your typical portable, right? Even a good one like a 189...?

mnem
mrrp?

[bitseeker]

i am pretty sure that i will never stop feeling, or acting, like an electronics noob. 

so.... nevermind

Learning and sharing is what it's all about. If we all knew everything already, what fun would that be?

[mnementh]

@wch -

Heh... it appears we both edited our post along the same line of thinking at the same time. Good... that shows you ARE still capable of deductive reasoning, and that I'm not wrong in reiterating things many of us consider to be common knowledge. 

mnem
"What a lovely library... have you read all these books?"
"Heavens no... who wants a room full of books they've already READ?!?"

[worsthorse]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

WAG-

PWM noise from nearby LED lighting or some device with PWM-controlled LED backlighting. Actually, nowadays, that's my FIRST guess anytime I see any weird "noise" type issue, as it has been proven right as a WAG so many times it's scary.  Closely followed by nearby WiFi/BT signal sources. Had to get rid of a favorite BT mouse/KB because it was effing noisy as hell. Okay, I gave it to my wife as her laptop is usually at the other end of the house.

That said... you are aware that these high-impedance, high-digit meters are generally a lot more sensitive to noise than your typical portable, right? Even a good one like a 189...?

mnem
mrrp?

yes... i know they are more sensitive to noise and at first i figured that is what i was seeing. and i probably will see that once i eliminate the errors i am introducing my own self.  what i have to keep re-learning is don't jump to conclusions which is what i did.

[mnementh]

Jumping to conclusions is such good exercise... but the accompanying diet of crow and self-deprecation can get a bit wearying. 

mnem
*hard-learned lessons*

[worsthorse]

Jumping to conclusions is such good exercise... but the accompanying diet of crow and self-deprecation can get a bit wearying. 

mnem
*hard-learned lessons*

dude, crow has been a diet staple around here for decades. i know more ways to prepare it than almost anyone. 

edit: honestly, i very rarely do things correctly the first time out. i may iterate many more times than twice before what i am doing/building/designing/writing/whatever looks much like whatever it is i intend to look like.  that's partly because i like figuring things out for myself, partly because i am not a natural at anything, and partly because i find that particular flavor of success to be more satisfying.

what's changed over the years is that i am much less concerned about failing in public than i was in my tender twenties and i am much more likely to admit my mistakes and tease myself when i do. 

[mnementh]

We should get together and write a cookbook... Maybe "Cock-A-Doodle-Do-o-o-n't! 101 Ways to Prepare Your Crow!" 

mnem
"Chapter 9: Self-deprecation is best served as garnish or light seasoning."

[med6753]

We should get together and write a cookbook... Maybe "Cock-A-Doodle-Do-o-o-n't! 101 Ways to Prepare Your Crow!" 

mnem
"Chapter 9: Self-deprecation is best served as garnish or light seasoning."

Chapter 10: To Trigger or not to Trigger. That is the question. Tunnel diode served on a platter.

[bitseeker]

"What a lovely library... have you read all these books?"
"Heavens no... who wants a room full of books they've already READ?!?"

Hmmm... 

[tggzzz]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

Could be external noise, e.g. spikes.

Could be internal noise, e.g. caps or the voltage reference or dirt/deposits.

My Solartron 7081 recommends that after being left in storage it is wrapped in a blanket, turned on, and left for a day. The internal temperature rises to ~40C. Mine improved significantly after that process.

[Zucca]

https://www.eevblog.com/forum/amphour/request-tin-at-the-amphour-show/

[med6753]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

Could be external noise, e.g. spikes.

Could be internal noise, e.g. caps or the voltage reference or dirt/deposits.

My Solartron 7081 recommends that after being left in storage it is wrapped in a blanket, turned on, and left for a day. The internal temperature rises to ~40C. Mine improved significantly after that process.

Like wise both my 5.5 digit DMM's, Siglent SDM 3055 and Fluke 8810A, need minimum 12 hours power on after a cold start before achieving best accuracy and stability.

[BU508A]

It got so bad I nearly bought Eagle. Then I realised Autodesk own them now so I crawled back to my position of taking it from the open source delegate minor devil rather than satan himself.

Jep. I've bought Eagle Version 7.5 right before it was sold to Autodesk. One of the biggest disadvanteges of the Eagle license
I have is its limitations to boards of a size of 160mm x 100mm. I planned to upgrade to a license without any
size limits but then I learned the pricing model of Autodesk. Do not have to mention that this is in my eyes a complete ... fraud? ... scam?
Wrote a comment in ther forum, that I was going to upgrade my Eagle license but not to such conditions. Since then
I'm working with my old license and are awaiting the day when I have to switch to KiCAD but I fear the learning curve.

Bloody thieves and highwaymans at Autodesk.   

[tggzzz]

sooooo.... i have four 5.5 digit DMMs, including a Fluke 8840A, on my bench. given the limits of my volt nuttery, i am happy that they all measure the voltage of a DMMCheck within 0.004 volts but...

they are kinda, i dunno, drifty, fluctuating, each and every one of them, in the least significant digits. and the changes are fast (every update when on internal trigger) and seemingly random (doesn't seem to be consistent in amount or direction). they don't settle down if I let them warm up. i guess it is a noise issue (WAG). i haven't done a lot of interwebbing to see if there is a reason or a fix and figured i'd ask the collective brain trust here for some guidance before i crack the cases open.

edit: to be clear, i see these fluctuations with the leads shorted, too, though the delta is a lot smaller. it is worse on the fluke than the HP meters. so it seems to be more than just the random nano current across a large resistance...

Could be external noise, e.g. spikes.

Could be internal noise, e.g. caps or the voltage reference or dirt/deposits.

My Solartron 7081 recommends that after being left in storage it is wrapped in a blanket, turned on, and left for a day. The internal temperature rises to ~40C. Mine improved significantly after that process.

Like wise both my 5.5 digit DMM's, Siglent SDM 3055 and Fluke 8810A, need minimum 12 hours power on after a cold start before achieving best accuracy and stability.

The "cooking in a blanket" process I outlined is more than that.

[mnementh]

@tggzzz: I like my readings to be a little unstable. I do my best work that way.

@BU & bd: Unless sometime in the last 5 years they've undergone major transformative overhaul been replaced by alien software lifeforms, using Eagle is still like trying to do brain surgery with a fucking rusty trowel. It really is a pernicious example of the old "Devil you know vs the Devil you don't" scenario... with a dash of testicular homicide and Stockholm Syndrome added in for local color. 

mnem
"I'd honestly rather stand in the middle of a busy intersection and drill screws through my feet." ~me

[tggzzz]

@tggzzz: I like my readings to be a little unstable. I do my best work that way.

I don't disagree; I like to see the bottom digit changing by one or two counts.