Test Equipment Anonymous (TEA) group therapy thread

[Saskia]

honi soit qui mal y pense

[tonyalbus]

done.... 70’s. to 2020

[bd139]

curve tracer voltage / current loop design. Currently uncompensated so this will no doubt oscillate like a wild monkey masturbating



sw1 sets voltage or current steps. sw2 sets step size.

Edit: looking at bias currents and stuff I’m going to have to add range switching for current sense for micro amp ranges. This gets really complicated really quickly. Need to build something that scales from 1uA to 10mA with better than 5% accuracy, universal stability under load level changes and a fair compliance range 

[mnementh]

Quick update on the toothbrush (I didn't think it would provoke so much discussion),...

It's Sunday, people are bored... 

I've just put my soldering iron away without re-tinning the tip. Ooh the excitement, ain't I a Webel!   

I lick mine when I'm bored. Sometimes I even turn it off first.

mnem
};=)~~~~<

[Cerebus]

curve tracer voltage / current loop design. Currently uncompensated so this will no doubt oscillate like a wild monkey masturbating



sw1 sets voltage or current steps. sw2 sets step size.

Edit: looking at bias currents and stuff I’m going to have to add range switching for current sense for micro amp ranges. This gets really complicated really quickly. Need to build something that scales from 1uA to 10mA with better than 5% accuracy, universal stability under load level changes and a fair compliance range 

You might want to consider a diamond transistor for that class B output stage, saves on the op amp rushing to turn one output transistor one and one off, and gives you better linearity for the cost of two jellybean transistors and two resistors without going all full blown V_BE multiplier. Like this:



I've put 2N3094 and 2N3906s but it can be anything really. In fact something a bit slower is advantageous as our old friends have so much more gain bandwidth than the BD139/140 pair it can get a bit hairy.

And yes, I can't manage to get my emitters in the right place first time today - it's been one of those days.

[Neomys Sapiens]

done.... 70’s. to 2020

What is that grey thing with the black and white wires in the lower left of the first pic which is absent on the second pic?

[mnementh]

did some long walk today including about 4 km through sand. Tired as hell.

Mmmmhmmm... so what was on the other end of the walk...? Something Nakamichi...? 

mnem
 

[Specmaster]

Well seeing as it was Sunday and a bit boring, my son and 1 popped over to Stansted Airport to see if there was much on and because we also knew that was a fairly rare plane coming in today, an AN-128P. This is an old technology plane these days, being an old turboprop, very smokey and noisy, Anyone in Central Essex would have heard it tonight around 8.00pm on its outward journey, droning away as it climbed to its operating level.

I also was given a 2.1 surround sound system with built in Blu-ray and DVD player (not working apparently but the rest is) which I shall test tomorrow, maybe it might make a further mention and photos here, we'll see.

Here a few of the photos I took of planes landing.

[med6753]

I think "UR" registry is Ukraine. Nice photo.

[med6753]

Older C-130's are almost as smoky....and noisy.

The big bad boy I'd love to see and hear is the AN-22. But I suspect noise abatement laws prevent it from operating here plus it would drive all the Angry Karen's batshit which would result in jammed phone lines to authorities. 

   

[Specmaster]

I think "UR" registry is Ukraine. Nice photo.

Correct it is

[Neomys Sapiens]

I think "UR" registry is Ukraine. Nice photo.

Correct

I think "UR" registry is Ukraine. Nice photo.

Correct it is

In the first look, I read it as 'UR COW'.

Moooo

[Saskia]

did some long walk today including about 4 km through sand. Tired as hell.

Mmmmhmmm... so what was on the other end of the walk...? Something Nakamichi...? 

mnem
 

The end of the road ...

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

[Zucca]

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

(Electric) bike could be an option, the weight goes on the sattle and your knees will thank you.
Of course you can get a cheap Lead battery one and convert it to LiPo...

[VK5RC]

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

(Electric) bike could be an option, the weight goes on the sattle and your knees will thank you.
Of course you can get a cheap Lead battery one and convert it to LiPo...

I don't see what the benefits of an electric bike are for health. Get a normal one and take it a bit easy at first, then start tackling the hills. In my mind the biggest problem is avoiding some crazy person driving a car and knocking you off. Mountain bike riding tends to avoid that issue so long as you don't get too confident and go plummeting down steep slopes!
Start here😉https://youtu.be/yotOZVELSMc

[Saskia]

Can't sit on a bike saddle after tumor surgery because of pressure to a nerve. My leg will go numb after less than 5 minutes. Been there, tried that with various different bikes.
Walking will work at 3-5 hours a day.

[bd139]

curve tracer voltage / current loop design. Currently uncompensated so this will no doubt oscillate like a wild monkey masturbating



sw1 sets voltage or current steps. sw2 sets step size.

Edit: looking at bias currents and stuff I’m going to have to add range switching for current sense for micro amp ranges. This gets really complicated really quickly. Need to build something that scales from 1uA to 10mA with better than 5% accuracy, universal stability under load level changes and a fair compliance range 

You might want to consider a diamond transistor for that class B output stage, saves on the op amp rushing to turn one output transistor one and one off, and gives you better linearity for the cost of two jellybean transistors and two resistors without going all full blown V_BE multiplier. Like this:



I've put 2N3094 and 2N3906s but it can be anything really. In fact something a bit slower is advantageous as our old friends have so much more gain bandwidth than the BD139/140 pair it can get a bit hairy.

And yes, I can't manage to get my emitters in the right place first time today - it's been one of those days.

Interesting idea. Will play with that. Thanks for the tip  . Saying that, in normal operation this doesn’t actually cross zero, just lurk at it so many be unnecessary. I’ll play further. Loop stability under all loads is worrying me more at the moment as I don’t trust it one bit 

Annoyingly I woke up at 6am today so have looked at the diffferential amp and it’s all wrong. I get the feeling I’m going to have to replace the current feedback amp with something a little more up market. Instrumentation amplifier here I come.

Also need a panavise as this thing is getting hairy now.

[tonyalbus]

done.... 70’s. to 2020

What is that grey thing with the black and white wires in the lower left of the first pic which is absent on the second pic?

That is/was the analog 2 wire phone system, infrastructure... we needed that hole in the floor for an extra power group/cable ;-)
well spotted

[VK5RC]

Can't sit on a bike saddle after tumor surgery because of pressure to a nerve. My leg will go numb after less than 5 minutes. Been there, tried that with various different bikes.
Walking will work at 3-5 hours a day.

Ouch, the one area of cycling there is no getting away from - even cycling shorts only help a tiny bit.
Walking is a great exercise - esp if there is a nice bit of scenery to enjoy - a beach is good - even if the weather isn't great - keeps the riff-raff away!

[tonyalbus]

Can't sit on a bike saddle after tumor surgery because of pressure to a nerve. My leg will go numb after less than 5 minutes. Been there, tried that with various different bikes.
Walking will work at 3-5 hours a day.

agree, walking is low impact on joins and muscle and has great health bennefits... well done Saskia!

[tggzzz]

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

Swimming is another option. Has benefits of being low impact and you can change the effort and duration.

[tautech]

Sold stuff and fixed stuff today.
https://www.eevblog.com/forum/repair/repco-ns-12v16a-charger-repair-log/

[Saskia]

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

Swimming is another option. Has benefits of being low impact and you can change the effort and duration.

agreed, however public pools/baths are a potential COVID issue and may be closed, or unsafe for German women to swim in.

The Baltic around this area is known to be somewhat dangerous due to strong currents, and besides, it's effing cold.

Walking's good.

[bd139]

Seriously, trying to get back in shape and get rid of some kilos by exercise. If yer too heavy to go jogging, walking seems to be an option.

Swimming is another option. Has benefits of being low impact and you can change the effort and duration.

People soup is never good for you.

[SilverSolder]

More walking, less eating.  Worked for me!