Trace inductance... Hobbs??

I will only agree to move into a retirement place if they let me keep my Weller, a scope and a few parts.

:-)

I never said we should stop, nor can I imagine fully stopping. Probably the last thud people will hear from me is the Weller iron falling out of my hand (and hopefully onto some safe surface ...).

Well, then you could finally buy that red Porsche without feeling guilty about it :-)

The Winchester Mansion (Mystery House) is a must-see!

Unfortunately I can't remember the restaurant name but, in Sunnyvale, about 2 years ago, a Taiwanese company took me to a Chinese place that was virtually ALL Chinese customers... HUGE... full of round tables... family style... fabulous!

...Jim Thompson

Which is why I added the disclaimer at the beginning. I was more directing the comment at the moronic types who are amazed that the Jims of the world are still working.

If I'd stayed there I certainly could have afforded a Q45. ;-)

Ah, but does that include transmission lines?

Tim

I have a Q45. I LOVE my Q45 ;-) The Nissan people tell me a new Z (more back to the original sports car version) will be here next year!

Crikey! I'm only _about_ to be 70. My Dad died last November at 90, great mind right to the end!

...Jim Thompson

Yeah but like I said, you gotta be a rich contractor to afford one of them. ;-)

That's what they said about the T-Bird, which ended up as a tarted up Lincoln LS. Yuck. SWMBO wants Mustang rag top, now that we're where the weather isn't as awful as the politics.

...and it seems like your 16th birthday was just yesterday. ;-)

My mother died in December at 95. The last couple of years weren't so kind to her, though she lived in her own apartment (senior center) until March or so.

If you have time to get up to San Francisco, I'll suggest the Exploratorium. It's the great-grandaddy of the hands-on sciece museum idea.

That's interesting....

Suppose you are getting old, but your brain still works. For simplicity, let's assume you are in a wheelchair and confined to your apartment.

How much junk/toys would you need to keep happy? (I'm assuming you get stuff through Digikey/whatever and eBay or any other place that takes orders over the web and delivers via mail/FedEx/UPS.)

How many dollars per month would you need for toys/parts to keep happy?

These are my opinions, not necessarily my employer's. I hate spam.

In Mountain View: The Computer History Museum

In San Francisco: Tut at the de Young

Jure Z.

Had it been a private or business page, I wouldn't have minded. But from a University it's outright disappointing. If you try to find out something you are not an expert in but trying to learn, pages like these make you waste most of your time on the web. I wouldn't allow the printout in the same room with my layouts :-).

Regards, H.

I advise you to have a closer look at "retirement places". Even years ago people were lucky to get a room for themselves. Not much space in there for additional hardware. My best guess nowadays is that we *may* be lucky, if we can keep a good puter with good simulation software and a web connection. ("Hey, nurse, could you please read this screen message to me!")

Regards, H.

One thing I forgot in my post yesterday (I was in a rush) was what you've already figured out - that including the inductance is not worth the bother in many cases.

A few years ago I went through this exercise on a large custom chip where the customer didn't specify that one signal path in particular had to be high speed, as in risetimes < 300ps. The trace in question was almost 4mm long! There was no substantive difference between lumped RC and RLC sims, RLC was just a few % slower even at these speeds.

BTW, there were other similarly long traces on this large die that _did_ pass signals at these speeds. Differential currents can be your friend, if you can spare the power.

steveg

Years ago, HD controller chip design for Silicon Systems... bipolar follower... layout guy ran trace clear across chip to its _base_, rather than keeping follower local and extending the emitter connection :-(

...Jim Thompson

Very little. When I was a kid I got nearly everything I needed out of scrapped electronics. Nowadays you can find jewels in there I wouldn't even have dreamed of as a kid. Like RF transistors in discarded cordless phones, for zero Dollars.

All I'd need for happiness in a retirement place would be if I could make others happy by repairing their electronic gadgets.

Same here, which is why I had to ditch the whole Google domain :-(

Actually I know a lot of those places because we have helped people move in there and visit folks. Unless you are very, very sick (where you can't possibly hold a Weller anyhow) there is some desk space available. One 82-year old lady runs the whole email prayer chain from her little room. She has a huge old-style computer and you can still fit two walkers plus a wheel chair in there. If you replace that with a netbook or small laptop that would free enough space for the Weller, a modern DSO and other toys. The hat rack in her closet is plety big for parts bins.

This is how the floorplan of her room looks:

The main issue isn't space but to cough up the $3000+ per month that the really good places cost.

I am not quite that picky :-)

All I can say is the Missouri-Rolla has helped lots of my clients understand root causes of EMI. Not scientifically but more like "Aha, that's why it happened". Good enough ;-)

Physically small inductors (and capacitors) can be measured with TDR. Big values allow observation of the L/R or RC (r=50 ohms) time constant; smaller values use the area under the curve-bump thing. I have an old Tek appnote around here somewhere...

No, it doesn't allow resistance. The program is cute: it uses the simple neighboring-averaging algorithm to calculate capacitance per unit length; then is assumes Er=0, V=C, and computes Z and L. Then it throws the real dielectric back in and recomputes Z.

John

Do you guys do Gerber file checks just like us board level dudes?

Of course, one can miss such little intricacies in the discrete world just the same, happens to all of us.