Test Equipment Anonymous (TEA) group therapy thread

[bd139]

As my physics lecturer said, it’s just a tiny little Mexican wave not a death race.

[tggzzz]

As I recall it's approx 1.2ns/ft delay.

At least that's what my still asleep and coffee derived memory is telling me. 

After coffee you will remember the physics homework calculation you did at school. Something like this, from https://en.wikipedia.org/wiki/Drift_velocity

Assume a current I = 1 ampere, and a wire of 2 mm diameter (radius = 0.001 m). This wire has a cross sectional area A of π × (0.001 m)2 = 3.14×10−6 m2 = 3.14 mm2. The charge of one electron is q = −1.6×10−19 C. The drift velocity therefore can be calculated: <derivation snipped> 2.3*10^-5m/s

Therefore, in this wire the electrons are flowing at the rate of 23 μm/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

[med6753]

Back in the S/370 days we had to time the system clocks to within +/- 2.0ns to their spec'ed delay to the master oscillator which was called "Gate A".  We adjusted and set the clocks with cards that had delay blocks and jumpers. To do the entire machine generally took about 4 hours. 

[bd139]

I’m glad I only have to worry about milliseconds at work 

[med6753]

As I recall it's approx 1.2ns/ft delay.

At least that's what my still asleep and coffee derived memory is telling me. 

After coffee you will remember the physics homework calculation you did at school. Something like this, from https://en.wikipedia.org/wiki/Drift_velocity

Assume a current I = 1 ampere, and a wire of 2 mm diameter (radius = 0.001 m). This wire has a cross sectional area A of π × (0.001 m)2 = 3.14×10−6 m2 = 3.14 mm2. The charge of one electron is q = −1.6×10−19 C. The drift velocity therefore can be calculated: <derivation snipped> 2.3*10^-5m/s

Therefore, in this wire the electrons are flowing at the rate of 23 μm/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

Nope, it wasn't via calculations and theory. It was observable on a scope.

[med6753]

I’m glad I only have to worry about milliseconds at work 

And luckily today's Z systems are self timing via microcode. In fact, the last time an oscilloscope was required in system's test was way back in the ES9000 days around 1990 or so. That's when the 475A's were retired. Today's techs have no clue on how to use a scope. 

[tggzzz]

As I recall it's approx 1.2ns/ft delay.

At least that's what my still asleep and coffee derived memory is telling me. 

After coffee you will remember the physics homework calculation you did at school. Something like this, from https://en.wikipedia.org/wiki/Drift_velocity

Assume a current I = 1 ampere, and a wire of 2 mm diameter (radius = 0.001 m). This wire has a cross sectional area A of π × (0.001 m)2 = 3.14×10−6 m2 = 3.14 mm2. The charge of one electron is q = −1.6×10−19 C. The drift velocity therefore can be calculated: <derivation snipped> 2.3*10^-5m/s

Therefore, in this wire the electrons are flowing at the rate of 23 μm/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

Nope, it wasn't via calculations and theory. It was observable on a scope.

"It" != electrons nor electron velocity, of course.

[AVGresponding]

In reality, the Swedish flag is nothing else but yellow and blue.

And being measurement people, lets define yellow and blue; Pantone PMS 116 C for yellow, and PMS 301 C for blue; which is equal to CIE x=0,472 y=0,465 Y=64,4 and x=0,189 y=0,192 Y=8,3.

The first definition was actually set in the swedish air force, who of course, being military, needed a instruction on how to paint by numbers. The definition was "guldgul och ljust mellanblå" and persisted as the only official regulation on colour until a law (1982:269) was passed with an addendum (1983:826) setting out the above values.

Yes, there are various reasons for this.

Historically though, while I was stretching it a bit to describe the blue as teal, gold is an acceptable definition for the yellow.


I'm a little surprised so many here are having mic difficulties, I've never had an issue using any standard headset, either wired or bluetooth, other than sometimes having to set defaults in windows audio manager.


The power supply for my differential probe has raised some problems; turns out the Chinesium DC psu is horribly noisy (like 2V pk-pk!) and even affects the Manson sat next to it. Who would have expected that?    
Also a problem with the Manson has surfaced. Though it's a nice noise-free output, there's an issue with long term regulation; set it to 15V for example and after a while it'll drop to 12V or so, then come back up later. Some investigation needed.
Also 15V seems to be near a winding changeover point, causing some changeover when coming on or off load sometimes.
Hope I can fix it, it's a nice little psu.

So, I've dug out the beast, my Thurlby dual o/p, and I'll try to wiggle it in to the space vacated by the other two.

I've also acquired another EP psu, 300VDC 500mA/90W, expected arrival late next week...   

[FransW]

Think of it this way:  When is a woman too beautiful?  -  this is what drives both audiophools and voltnuts, I suspect.  Are they wrong?

Don't forget the time nuts. They might be feeling lonely.
Frans, in search of the Planck time.

[Specmaster]

As I recall it's approx 1.2ns/ft delay.

At least that's what my still asleep and coffee derived memory is telling me. 

In my slow functioning brain this morning, something keeps telling me from my college days that it is not that simple. It has far less to do with the cross-sectional area of a conductor and more to do with surface area as electrons are freer to move on the surface then they are through the core of the conductor, (swigs another big swallow of coffee to combat sleep due to bad night) and also of course the conductive material itself will play a big part in the speed of the electrons.   

[med6753]

Specmaster guessed it correctly. Leather activity related to TE. New handles for the 535A. I've never worked with leather before and I'm a complete neophyte. But I got one done and while not the prettiest thing it will be serviceable. Now to complete the other one.

   

[Specmaster]

Specmaster guessed it correctly. Leather activity related to TE. New handles for the 535A. I've never worked with leather before and I'm a complete neophyte. But I got one done and while not the prettiest thing it will be serviceable. Now to complete the other one.

   

Yah, I got it right, I also knew that it was for the 535A because you mentioned them before. They don't have to be the prettiest think thing around, just functional and safe, that is a big heavy beast to have to manhandle without some form of working handles 

[Cerebus]

In reality, the Swedish flag is nothing else but yellow and blue.

And being measurement people, lets define yellow and blue; Pantone PMS 116 C for yellow, and PMS 301 C for blue; which is equal to CIE x=0,472 y=0,465 Y=64,4 and x=0,189 y=0,192 Y=8,3.

Well of course you're both wrong. A flag, being a heraldic device, doesn't have a colour, it has a tincture, and the heraldic tinctures in question are or and azure. TFTFY 

[AVGresponding]

"or" meaning gold, ofc...   


EDIT: The beast is looking very good for line and load regulation, less than 70mV rms noise, messy load switching makes it put out 200mV spikes, neither of which are likely to be an issue for temporary powering the probe for testing purposes.



My improvised load device...


Wow, I really need to clean my bench a bit...

[Mr. Scram]

Why can't we have nice things? Now a thread about certifications is turned into a patriotic US Chinese shitfest between usual suspects. I want to talk about certifications damn it.

[med6753]

Why can't we have nice things? Now a thread about certifications is turned into a patriotic US Chinese shitfest between usual suspects. I want to talk about certifications damn it.

Location of the asshattery?

[Kosmic]

Why can't we have nice things? Now a thread about certifications is turned into a patriotic US Chinese shitfest between usual suspects. I want to talk about certifications damn it.

Location of the asshattery?

https://www.eevblog.com/forum/projects/bring-a-product-to-market-without-certification/

[med6753]

It's done and reinstalled on the scope. I'm quite pleased with how it turned out. Secure handles but it doesn't really make it much easier to jack ass around. 

[bd139]

Looks like a bondage smurf 

More seriously, nice job 

[mnementh]

As I recall it's approx 1.2ns/ft delay.

At least that's what my still asleep and coffee derived memory is telling me. 

mnem



Full, historic lecture by one of the greatest minds of this era:

[med6753]

Why can't we have nice things? Now a thread about certifications is turned into a patriotic US Chinese shitfest between usual suspects. I want to talk about certifications damn it.

Location of the asshattery?

https://www.eevblog.com/forum/projects/bring-a-product-to-market-without-certification/

Ah yes, one particular individual has an ego so big he can't fit his head through a door and he doesn't like to have it bruised either. 

[Cerebus]

Why can't we have nice things? Now a thread about certifications is turned into a patriotic US Chinese shitfest between usual suspects. I want to talk about certifications damn it.

Sigh.

Does anyone remember the Internet Protocol evil bit? What we need is an IP 'patriot' bit, then national border routers could just drop those packets and all the people who think that their country is the greatest, the only true, pure, country and all the rest are scum couldn't be heard outside their own borders and wouldn't have to, indeed wouldn't be able to, interact with all those grubby second and third rate foreigners.

Also at the moment it would prevent them getting balanced, accurate, nuanced information about the current disease threat from Covid-19 from outside sources, and would limit them to patriotic propaganda. The lack of information on how to properly and proportionately protect themselves might have a salutory evolutionary effect.

[Mr. Scram]

Ah yes, one particular individual has an ego so big he can't fit his head through a door and he doesn't like to have it bruised either. 

There seem to be a couple of usual suspects who take endless threads hostage with their waving of the flag of whatever patch of Earth their mother decided to push them out on top of.

[mnementh]

   It's done and reinstalled on the scope. I'm quite pleased with how it turned out. Secure handles but it doesn't really make it much easier to jack ass around. 

Looks like a bondage smurf  More seriously, nice job 

Needs more spikes. And a terrifying Nordic-looking woman grinning contemptuously while smacking a riding crop against her palm next to an enormous Great Dane.

mnem
Don't forget the fuzzy handcuffs. She really likes those.

[Mr. Scram]

Sigh.

Does anyone remember the Internet Protocol evil bit? What we need is an IP 'patriot' bit, then national border routers could just drop those packets and all the people who think that their country is the greatest, the only true, pure, country and all the rest are scum couldn't be heard outside their own borders and wouldn't have to, indeed wouldn't be able to, interact with all those grubby second and third rate foreigners.

Also at the moment it would prevent them getting balanced, accurate, nuanced information about the current disease threat from Covid-19 from outside sources, and would limit them to patriotic propaganda. The lack of information on how to properly and proportionately protect themselves might have a salutory evolutionary effect.

I can see that working but we'd need physical firewalls at the borders too. Not just lame border walls but flame throwers and laser grids. Otherwise the echo chamber starts building a resonation until the chamber burst violently and neighbouring countries start being invaded.