One reached moon orbit from a transfer orbit. It took 18 months... and wasn't a real lifter because it used xenon that it carried along and not atmospheric air.
The mass-to-thrust rations of there are lousy: often tenths of a newton, leading to milli-G acceleration.
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This is the closest I suppose.
BTW the ion engines use an electron gun to stay electrically neutral - or all the ios wouldk be attracted back into the vessel, damaging it and zeroing the performance of the engine.
John, I really don't see why you're arging this point. The "thin nylon wires" are used to hold the lifter in place so it won't fly away. They are not the conducting wires for the power supply. Lots of amateurs have made lifters with no tethers: they usually fly up far enough to disconnect the power supply wires or damage the lifter. There are many web sites online discussing the lifters which you can find by Googling. You can write the authors of these web pages if you don't believe how they work.
Guy conveniently snips my next quoted paragraph, where I spell out my reasoning and it was clear one didn't have to read carefully...
Oh well...
John, you're sticking up for Guy? Wow! But then, he surely won't appreciate this, given that he doesn't think you're a real engineer.
"Because he is under the mistaken impression that he is an engineer," with which Guy begins a lengthy full-on rant against you, finishing with his pompous, "THE STANDARD ADVICE:" for all of us decade-long inhabitants of this newsgroup to read and appreciate, NOT.
No, of course not; it was Rich who said he aspired to silliness, and I was expressing my admiration. Silliness is often a great source for ideas. I don't expect that GM often allows himself to get silly; he's too busy trying to convince himself and us how important he is.
I don't care what people call me. I just design electronics, and all that matters is whether people buy it. GM's rantings say a lot more about himself than they say about me.
Did you eyeball the lectures he delivers on his web site? Bizarre.
But...
How come nobody makes any decent 44-volt-supply opamps in SOT-23? I have a place where a lowly 741 would be ideal (inside the loop of a chopamp, so accuracy doesn't matter, just need a lot of output) but I can't even find it in SO-8, much less SOT. National shows an SO-8 LM741 on their datasheet, but it's not shown as available for purchase. ON has a couple of weird parts, MC33071 and such, but sole-sourcing these is scairy. We're trying to pack a huge amount of analog stuff (dc/dc, data isolation, main dac+mdac, test relay, output amp with protection) into under 2 square inches, and DIP8's aren't very appealing.
Every damned analog thing will soon be 5 volts max, if not 3.3.
--
"I even"...? Just more of your narcissitic bullshit, Macon.
>
> THE STANDARD ADVICE:
>
> There is a way to influence what gets discussed in a newsgroup that
> works well, and another way that has never worked no matter how many
> people have tried it.
>
> What works: Post articles on the topic you wish to see discussed,
> and participate in the resulting discussion. Use killfiles and
> filters so that you don\'t see the articles that you dislike.
> If you don\'t know how to use a killfile, use good old fashioned
> discipline and don\'t read the articles that you dislike.
It already is. Just about everything I'm working on right now is 3.3V or LOWER :-(
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |
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| 1962 | I love to cook with wine. Sometimes I even put it in the food.
Somebody recently announced a process that puts a tweakable floating gate inside a regular cmos fet, so the threshold can be set to anything, including zero. They have built circuits that work at Vcc of
20 millivolts or something absurd like that. People like this are evil and should be punished.
Apex had a nice 400-volt CMOS process (actually fabbed by AT&T, I think), but a bit noisy. 20 micron design rules or something.
I can predict that you're not going to be much help with my problem.
Because he is under the mistaken impression that he is an engineer. A real engineer has the all-impotant attribute of listening to what people tell him. You can tell Larkin how lifters work and explain that the only reason they have wires going to them is because the power supply is too heavy to lift all day, but it won't get you anything but questions and - eventually - personal abuse. Ignore him.
Have you calculated whether a big stack of coin cells driving a DC-AC inverter and then a Cockroft-Walton stack will be light enough to fly yet? what number are you getting?
You are wasting your time explaining. Usenet being what it is, I strongly advise you to look at how helpful each person who responds to you is and to not reply to the non-helpful. I even wrote up a nice explanation of how this works so folks can quote it. Here it is:
THE STANDARD ADVICE:
There is a way to influence what gets discussed in a newsgroup that works well, and another way that has never worked no matter how many people have tried it.
What works: Post articles on the topic you wish to see discussed, and participate in the resulting discussion. Use killfiles and filters so that you don't see the articles that you dislike. If you don't know how to use a killfile, use good old fashioned discipline and don't read the articles that you dislike. Never, ever respond to articles that you dislike.
What doesn't work: Respond to articles that you dislike, complain about articles that you dislike, complain about posters that you dislike, complain about how terrible everyone else is for not posting what you want them to post. Talk about how to respond to articles that you dislike. Make the articles that you dislike the center of attention, the main topic of discussion, and a personal crusade.
I made many posts in 1994, more or less 11 years ago, but reading them I'm forced to conclude there were many before that as well. I've lost access to most of my computer records from that period. Most of the posts were not about AoE, but about various technical issues that interested me.
Those I-V curves are not unfamiliar to someone who has used CMOS fault-protected multiplexers, such as the HI-5108 (AoE page 150), max358, adg438 or dg458. These switches disconnect the signal if it goes above the supply rails. But these parts quickly run into trouble if the signal gets too high (e.g., over +/-25V).
For a precision series-protection current-limiters I like to use a pair of back-to-back LND150 or LN250 depletion-mode MOSFETs. These have the advantage of protecting to over +/-500V. They do present 2k-ohms of series resistance, which can add some Johnson noise. If that's important the 180-ohm dg458, or your new 80-ohm adg465 might be preferred, but only provided that you can keep the excess external voltage to under +/-35 to 40V. That fairly-low working voltage seems rather limiting to me. :>)
I haven't designed with toobz since 1963 (with a few exceptions), yet my trend has been to higher rather than lower voltages using semiconductors. My latest amplifier works over a 2500V range and 100 of them (smt machine assy) will be built into one experiment.
Low-voltage may be fine in a cell phone, but there's a physical world out there that needs to interface with real-world physics.
Agreed; I'd prefer something that could stand AC line voltage and transmit 15 or 20 mA of signal. The LNDs are great when you can tolerate the low Idss. At least the 465 allows my customers to mis-wire a 24 volt circuit - pretty common in their biz - into my dac thingies. Claire has a new opto ssr that's self-protecting, maybe worth it as a limiting element alone.
We were playing with polyfuse/transzorb combinations, but couldn't come up with a comfortable arrangement, especially with the space restrictions of this project.
I can't really remember when I first found Usenet, but the first Google-mention I can find was August 1995.
Trying to recall, that would be about the time I got a "high-speed" connection... DSL, then I switched to cable about a year later, when it became available out here in the "boonies", though we're "boonies" no longer... about 100K people out here in Ahwatukee Foothills now.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I did some 30KV stuff for Woodson/Jackson/Melcher in 1961-62, but my last tooobz audio was around 1957.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Well, duh, it's absolutely a matter of the power supply. Duh.
You impart kinetic energy to your reaction mass. For every action there is an equal and opposite reaction [whoa, dudes! The Philosophizer just had a huge metamental rush there!].
It's not like the air you're shoving down is pushing against other air - it's pushing against the underside of your propellor/impeller/ rotor/electrode! Think of the people in Newton's time, contemplating a rocket: "Push against your own ass? Preposterous!" But, yes, to move something, a force has to be applied to it, and that force has to come from somewhere, and that would usually (in the experience of every living being there's ever been since the beginning of time) be The Power Supply.
Well, not the electric levitation kind, but there have been self-powered untethered craft that have got up off the ground.
ISTR it required copious amounts of input power, such that keeping the craft supplied with fuel was the primary major issue.
Oh! I got it! These lifter crackpots are looking for antigravity!
Well, hell, just get in touch with your own atoms and their gravitic field, and ask your own personal gravitic field and Mother Earth to do a levitation trick. ;-)
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