a question about resistors in an arc experiment

Hell of a qualifier.

Yeah, a small positive number like +0.05 beats -1. I won't name any names.

John

Oh, that part's easy. Sure, do some transient trick, or better yet simply design in the power level from the start. But transient analysis is an insane, probably impossible way to optimize temperature stability and phase noise, which lots of people really care about. We're talking parts per billion here.

John

Yes, I used to date a simple pole, and I know exactly what you mean.

John

You mean a non-existent active circuit would be the equivalent of an equally non-existent passive component?

There's some logic to that line of reasoning, I suppose.

But as an argument in support of the idea that it's possible to construct a circuit that behaves the way a passive negative resistor would, without needing a power supply, it has an obvious limitation.

Sylvia.

LTSpice only does one type of negative resistor. I think it actually converts to conductance as the first step.

One type of negative resistance is unstable for a high impedance and the other with a low impedance.

I'm more concerned about designing circuits that actually work than debating the meanings of words. You keep doing what you do best.

You seem to be assuming that I am Master of the Universe, and resenting my superpowers. Get used to it, mortal.

John

Aren't both kinds unstable if connected to a capacitor?

Imagine a SOT23-6 with pins...

V+ V- R+ R- Z+ Z-

When you connect a resistor between R+ and R-, the chip presents -R at the "Z" terminals.

We met with some LTC people last week. I suggested a couple of ICs I'd like to see... not including this one. They politely agreed, but told me that the reality of designing a linear IC isn't the presence of a good idea, it's having a launch customer who will buy a few million of them.

John

The circuit was both original and correct. It debounces a switch and obviously produces a clean positive glitch, with a minumum of parts. If somebody wants a negative glitch, it's trivial to modify. The circuit was a gift, not a challenge, and was accompanied by no personal comments of any sort.

Quit whining and post some circuits that are either original or correct. And if you do include insults and challenges, I'd suggest you make some small effort to be right, or even the skinny girls in the group will cheerfully whack you.

How's that?

John

Speaking of Lenny, the only thing by him I've actually heard didn't have any "dirty" words - he substituted the word "blah". This apparently got people more up-in-arms than if he'd said the actual "bad" words - obscenity, after all, is in the mind of the beholder. ;-)

"The man puts his blah into the woman's blahblah", that sort of thing.

Heck, the man might have brought the cloves for the ham! ;-)

Cheers! Rich

Well, excuse the bloody hell out of me.

Thanks, Rich

Maybe *you* were, but everyone else had a clue.

select it with the move tool and hit ctrl-R twice stick it back where you found it.

yeah it'd be nice to be able to do that with the current probe tool. Actually it'd be nice to be able to reverse the polarity anywhere the current probe can be used. (eg -ve supply of the op-amp)

The two of you need to settle on some terminology.

There's the resistance defined by V/I, the large signal, operating point, or whatever you want to call it 'resistance'. Then, there's the small signal, differential, or region, defined by dV/dI.

Sylvia is referring to the former, you, the latter. Each definition has different implications for stability, power dissipation and other properties of a circuit.