That's the circuit I used, in a box with two 9-volt batteries, in my class project ca 1968. I used a 709 opamp, as I recall. It was fun, plugging negative numbers into all the classic circuit equations and seeing the actual waveforms.
Sylvia should try it.
John
It works fine in LT Spice. A -10 ohm resistor connected to a 1 volt battery charges the battery at 0.1 amps.
Perhaps you meant "simulate in hardware." If that's what you meant, you should have said so.
John
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There's (at least) one nice direct application of this idea - compensating for the winding resistance in a DC motor speed controller.
-- John Devereux
I think it's accurate to call the hardware circuit an *emulation* of a negative resistor. Which can of course be simulated :) But the hardware implementation is - or has - a real, physical, resistance.
-- John Devereux
You can do that in power supplies, too, to make up for wire resistance to a remote load. A lot of hysteretic buck switchers have inherent negative output resistance, for reasons I don't know.
John
I withdraw my "smart girl" comments.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
slope
Well, the point is to have fun with whatever anybody posts, isn't it?
John
Yeah, I just said it was nice to have a girlie around. :)
Maybe she's cute.
On a related note, I was just contemplating the wisdom of the 19th ammendment, when I remembered that it was immediately preceded by 3 foolish and regrettable ammendments which men alone voted for.
-- Reply in group, but if emailing add one more zero, and remove the last word.
This is SOP in brush DC motor drives. It is called "IR Compensation" in the industry.
Kilovolts? Where do the kilovolts come from, and when?
John
If you actually know anything about the electrical properties of arcs, say so. Seems what you mostly do is juvenile he-said-she-said crap.
John
power.
He should have listened to them. He might not have died of a morphine OD.
John
-- Yeah, he might have died of boredom instead. JF
-- Oh, don\'t be a PITA. JF
power.
See the movie. He was a very stressed-out individual.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
You make my point, and in the least original way possible.
John
power.
-- Just trying hard not to confuse you, John. JF
From the negative resistor, of course. As the current approaches zero, the voltage approaches infinity. ;-)
Hope This Helps! Rich
That *does not help* !
John
Usually, when an electronics engineer draws an opamp, he's not trying to pass the circuit off as something it isn't.
Sylvia.
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