free energy!

I used The Thompson Trick:

Start with 1 ohm. Simulate and display the current. Change the resistor value in the schematic pane. Screen capture *without* re-running the simulation. Post the image but do not post an .asc file for other people to try.

It's faster than using Photoshop.

I gotcha. Thanks!

Marvelous... Glad you're happy.

Duh? How does that change the RAW file showing NEGATIVE power?

You really do need to pay attention... I _did_ change the schematic, then _did_ re-run the simulation, got the negative results.

Tracked it down to a "save"/"not-save" issue, which I _did_ post what I found... several post layers back.

Nope.... that's how I caught that it was the "save"/"not-save" issue... as soon as you "save", rerun the schematic, you're back to positive power.

(Incidentally, PSpice doesn't require "saves" between simulation runs... lets you go BACK around 50 versions if need be. "Save" erases the history. That's what snagged me... I only "save" when done for the day. Immaterial to this discussion, you can't buy my version of PSpice anymore.)

You're always glad to go out of your way to be an asshole.

My mistake was reading your "free energy!" post in the first place :-(

But enjoy yourself!

I'm adding to my terms and conditions:

"You're free to follow along with the design of your chip using LTspice. However any time required by Analog Innovations staff to demonstrate to you that LTspice can give false results will be billed to you at an extra charge of $250/hour."

Chortle all you want... recently had a customer harp at me that LTspice reported that CMOS device sizes could be significantly smaller than what I showed. Had to spend nearly a day getting the simulation transferred to a Cadence Virtuoso environment to demonstrate that PSpice and Cadence simulations were DEAD-ON matches... LTspice was wrong. ...Jim Thompson

He changed the schematic AFTER the simulation. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

Duh! How did the negative power get there in the first place? ...Jim Thompson

Thanks, I just learned that.

You can make the change and rerun the simulation without resorting to a SAVE. That way you can undo your change(s).

How'd they do that when the foundry models are encrypted?

Cheers

Phil Hobbs

Of course, if you re-run the sim after changing the schematic, the sim agrees with the schematic.

If you won't post an .asc file, and describe the use sequence, nobody can reproduce your negative power. All you generally post is screen images.

Am 07.03.2018 um 18:22 schrieb Jim Thompson:

There is probably no good complaining for your customer.

"This program is specifically not licensed for use by semiconductor manufacturers in the promotion, demonstration or sale of their products. Specific permission must be obtained from Linear Technology for the use of LTspice for these applications."

BS. The foundry models aren't encrypted. ...Jim Thompson

Please learn to read _every_ word before jumping to the wrong conclusions. Sheeesh! ...Jim Thompson

Yep. I'm aware of that, but seems like every customer in the world has decided they're a Spice expert >:-}

I'm pondering, and will need to run it by my lawyer... adding a fee to pay the Cadence/Virtuoso provider for his inconvenience ;-) ...Jim Thompson

Sometimes, but not always (really strange), you can get negative power... seems related to whether (in the resistor case) there's a "hard" voltage across the resistor, or if it's immersed in circuitry that isolates it from a "hard" voltage source.

It's not my problem anymore. Why should it be my concern if _you_ get flaky results ?>:-} ...Jim Thompson

Please post a case that other people can reproduce.

What you are saying is that you can't reproduce the problem such that other people can verify the claimed bug. If you could, you certainly would, instead of slinking away.

I think that you probably ran a sim, then flipped the resistor, then did the alt/click thing to plot power **without re-running the sim**

New schematic, old simulation data. That does indicate negative power. That's not a bug, that's silly/amateur procedure.

Just as soon as you post the ASC file for the circuit for which you first claimed "free energy!" >:-} ...Jim Thompson

Just stick a bit of wire in the wrong place. I'm not recommending it :) A bit more seriously one always needs to begin by defining terms on topics like this.

NT

Hmm. Trusting souls. ;)

Cheers

Phil Hobbs

By definition, power dissipation in an object that has no internal source of power must be zero or positive.

LTspice has some bizarre behavior that seems to be related to two things, (1) was a "save" executed, or not, between sims, and 2) is the component (resistor seems to be vulnerable) isolated from a direct "hard" power source... don't know how transistors might behave, but Larkin claimed his negative power was in a transistor, with a value way to large to be rounding error.

I see no point in further wasting my time on a subject that no one else actually has a scientific interest in pursuing... just casting stones at me because I questioned the sacred cow ;-) ...Jim Thompson