X5R vs X7R MLCC

Another question: If you make an ohmic connecton to a resistive plane, the contact resistance goes up as the contact size goes down. In the case of our plane impedance here, does the contact size matter?

If I can't find 1, 2 will be even harder.

I got to tutor my son and his girl friend* in calculus yesterday. A fun time, a lot of their problems come from 'simple' algebra mistakes.

George H.

It is definitely creepy. Don't give the girl friends even the slightest hint of your thinking.

How would you stack up as potential grandfather material - as in free child care resource. My younger brother has some eight grandchildren. Three of them are in Hong Kong (or were at last report) but the other five keep him and his wife busy.

Calibrated amplifiers and a useful trigger? Delay line?

Your labor cost?

In fact, academic study is designed to kill interest. You're in at least a couple years before anything interesting in the major comes along. It could be much different but it seems that's the way it's designed (flunk-out courses abound too).

Does anyone care what Slowman believes anymore?

Absolutely. They have no interest in teaching anything useful. Academics is for academic purposes only.

As long as that's all you're eyeing. ;-) h

Ours was in excellent shape. There were six or eight students (myself included) paid to keep it working and calibrated and two full-timers. It was all tested and calibrated over the summer and calibration checked during the semester/Christmas break. Tektronix and HP were major donors of top-of-the-line equipment (all matching lab stations).

Sounds like my chemistry labs.

Great idea but I've been hearing the same song for forty years. Doesn't work that way.

Doesn't work that way. The performance hit is too big. Noise, and all that.

OTOH, these guys were in last week and had some interesting products. Not sure if it'll work for us but there may be a place.

"Almost"

Certainly not. Your genes deserve the best company.

Breeding strategies are multi-generational.

ferent approaches. I don't relate to the learn it all in uni then practice a little style, and watched people that did look like rabbits caught in hea dlights when asked to design & make something.

rking in the lab was a huge waste of time & did the project at home. From t he limited amount I've seen of unis they seem to miss out that cost effecti ve way for students to learn. And they entirely fail to motivate students t o do so.

d, academic study without practice or interest is poorly understood & quick ly forgotten.

lots of circuits, and along the way the student finds something of interest s & wants to build it. Keep building interesting stuff & the need for acade mic learning crops up along the way. That's basically how I did it.

lly. It resulted in plenty of parts though.

Does krw believe that anybody believes anything different from him?

He doesn't care what anybody else believes, and seems incapable of believin g that they sincerely disagree with what he "knows" to be true.

This leads to him making utterly fatuous claims at regular intervals.

a lot.

This is typical of the kind of bizarre nonsense that krw makes a habit of p osting. In fact universities are forever adjusting their courses to make th em more "relevant".

When I was a graduate student I did a newly introduced first year course ca lled "Theory of Computation 1". If krw's asinine theory was right, the univ ersity would never have introduced it.

Another bizarre misconception. My Ph.D. supervisor - the professor of physi cal chemistry - used to consult for the mining industry on the side.

Academics are well aware of the practical applications of their specialties , and quite a few of them make money on the side from these practical appli cations.

When I was working at Cambridge Instruments I used to run into Alec Broers from time to time - he was then professor of electrical enginee ring.

I'd met him at a college dinner, so I'd say hello. I'd already known that h e was part of the electron microscope Mafia, and that he'd invented the LaB

Perhaps not the kind of academic that krw would meet ...

How could they be anything else?

The idea is recurring. I remember presumably general chips with custom top-layer-metal, from decades ago. They were apparently mediocre at both digital and analog functions.

RAM-based FPGAs killed off mask-programmed and fuse and antifuse technologies. So RAM programmability is probably the most sensible way to program a mixed-signal chip; design iterations in hours, at the customer site. I think the problem is coming up with decent, general analog parts.

Switched-cap filters are generally awful.

It's creepy to imagine doing analog design (and maybe PC boards?) in a programming language.

The part where the square pulse comes down and softly levels off, is the hyperbolic region (Z ~ 1/t). Apparently it levels off very quickly compared to 50 ohms, so the time/div isn't very good here for identifying what the curve really is like.

In the ramp region, it seems to be bouncing between the board and the TL stub. The fast squiggles in the bend may be board parasitics (bouncing between edges, vias, stubs?).

I'm a bit confused on the length scale. The TL stub looks more like half a ns, but it measures about 2ns according to the scale. Maybe it's longer than the head of the probe box dongle thingy.

Not enough to be helpful it seems (where "helpful" would be, say, Q < 3), if you need very low impedances without kinks. Unless that bouncing is due to the TL stub. Again, dunno.

What's ohmic? If it's a rubber sheet problem, then static solutions apply.

In terms of via diameter, that's rolled into the inductance formula.

Tim

things much better. More often than not it fails for me. Last time I used i t just recently it thought transistor V_be didn't drop at low current, maki ng it not useful. A lot of stuff I don't Spice at all, I understand it bett er than Spice does. I'm sure there's lots Spice knows I don't, I just tend to operate in a space where it doesn't & isn't helping.

They're simplified in order to run in sensible times on our limited computi ng power.

I can't wait for the day we have not a few GHz of CPU but a few hundred. Bu t by then I might wish to be younger instead.

NT

that's one way to miss the point.

krw wrote

Consider it study cost. Was just fun, you learn a lot, and use that in your job and it pays back there.

Designing and building things like your own test equipment and whatever is of enormous value. Any idiot can buy a 1 GHz sampling scope and then if you have no clue how it works how in the world are you going to use it? Draw conclusion from what it shows? For WHAT? Same for anything else.

The advantage of an electronics hobby is sometimes that you have everything. Others spend it on booze or women or cars or boats. Well OK I tried that too.

Or bring out one more point that NT doesn't seem to have thought about.