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Re: CPU question
Jim Purcell
Saad,
Old PC's can beI've heard about that but I wonder whether it is a practical idea. The controlling software that would assign parts of the computing task to various computers would have to be vary sophisticated. Then there would be the distances between computers. It would probably be better to just use the system cards otherwise all those old power supplies would consume lots of energy and there'd be the problem of varying power supply connectors and voltage requirements, maybe some kind of bus communication would be necessary to avoid port bottlenecks. It would certainly be a good project for some IT students but I think the work involved in making it happen in a real world situation would more than cancel most benefits. But then I could be wrong, wouldn't be the first or last time. Jim |
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Re: optoisolators
Borut Wagner
¿ªÔÆÌåÓýYou
may use transformers, which are made for telephony?(here in Slovenia we use
300-3400Hz bandwidth?for POTS, I don't know what is in USA, but I
think?it isn't much different). Ask in Radio Shack
store.
?
Best
regards,
?
Borut
from Slovenia.
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LM3914 vs LM3915 vs LM3916
Curtis Sakima
I saw on this group .... somebody wanted to know the
difference between the LM 3914 / 3915 / 3916 ?? I accidentally erased that original email so I can't recall what the original question was!! Anyways..... You're right ... that schematically, the LM39XX chip ARE the same. The ONLY difference is the CALIBRATION. The 3914 is a linear-ly calibrated device. It's output changes one-per-volt (or per-amp or per ohm or whatever) The 3915 is LOGRITHMILLY (maybe someone could correct my spelling!) CALIBRATED. The 3916 is calibrated by dB's (like in audio/VU metering etc). It's output changes one-per-(audio)dB. Now I'm NOT sure what the difference is between LOGRITHMILLY (again, spelling) and DB calibrated is. I've always thought that dB's WERE log. I just know that because once upon a time a project required me to read the spec sheets and that is what it said. So I thought I'd pass it on. Hope that helps!! Curtis ===== * * * * Your website deserves a taste of rush hour traffic * * * * * * __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. |
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555 Observation
In my class today, I hooked a 555 in astable mode to an o'scope.
Before powering up the scope, I centered the trace. After powering up the 555 I noticed the output from pin 3 was going from +v to -V (I didn't check the voltage scale, so I don't know how large V is). I don't understand why that happened. I should have gone from 0V to +V. Am I missing something? Paul |
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Re: International agreement on allocation of frequencies.
Jim Purcell
angtengchat,
Is there an international agreement whereby each radio / tv station fromYes, each country has allotted bands, sometimes shared. For example in N.A. Canada and Mexico share our broadcast band, to the delight of broadcast DXers. (DX = distant) who listen to distant radio stations. One interesting frequency is 800 kHz, where a Windsor, Ontario, CA has a 50 000 watt station and the Netherlands Antilles has a 500 thousand watt station. DXing those can be fun, I have heard both in Milwaukee, but not at the same time. Jim |
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Re: Fw: communication concepts ??
Jim Purcell
angtengchat,
Seeing how you could do calculations and your detailed explanation, ISelf education is an alternative. That's how I got my initial training, two home study courses. The second got me my FCC license and a job in broadcasting. That was a good learning opportunity. A broadcaster had to be jack of all trades and was seldom master of any of them. Jim |
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Re: newbie inquiry
Jim Purcell
angtengchat,
Discarding time factor, in short, it is the current passing thru that bodyYes, I agree, especially at higher voltages. OTOH look at how long some people take to die in the electric chair. And when there are problems sometimes a person doesn't die and they have to go through all that again. I would favor a law that says a person who goes through that once automatically has his sentence commuted to life... without parole. Jim |
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Re: PIC resources
Teodoro M. Villamarzo
Hi Mounir,
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Thanks for the concise definitions. I suspect that you can make mechanical devices using them. Maybe even a small robot? I haven't seen one, though. Are they commercially available? And how do you program them? Ted At 04:12 AM 11/1/01 +0000, you wrote:
Hi Ted, |
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Re: PIC resources
Mounir Shita
¿ªÔÆÌåÓýHi
Ted,
?
Yeah,
actually I'm currently working on putting a PIC into a toy
robot.
?
They
are available commercially. Actually, PIC are one of the most popular
microcontrollers among hobbyist. You can by them at about any electronic
component store/distributor. Check out for example. To program them
you either:
?
(1)
Need a programmer. Which can be pretty expensive. But if you have one of those,
then you're set for a long long time.
(2)
You can get a In-Circuit Debugger which will program a few Flash
parts.
(3)
Make your own programmer (tons of schematics for this on the web) and use
in-serial programming.
?
Mounir
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Re: Fw: communication concepts ??
Doug Hale
I wouldn't let that stop me, I have the degree but I don't work in that field. I am completely self taught in the field I currently work in, and the one before that, and the one before that, ...
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You can do ANYTHING, you just have to decide to pay the price. (study) The key to electronics is math. Math is nothing more than a modeling language. It provides us with a way to model/describe natural behavior in an unambiguous may. My formal training is mainly in Control Theory. My first job out of school was in computers. I learned digital electronics from Manufacture's data sheets and application notes - primarily Signetics because they gave them away instead of charging for them. I got my BS in 1975 but I have never stopped learning. Learn from whatever source you can find. The web is full of stuff, course materials, data sheets, application notes, white papers, ... There are some good beginning books at the ubiquitous Radio Shack. I f there is a college or university near you, you can find some real good used text books - and actually the older the better. My favorite sources are still my OLD college texts (yep, I've still got them all). But most of all, have fun and enjoy what you are doing, it makes overcoming the difficult thing that much more rewarding. Doug Hale angtengchat wrote: Seeing how you could do calculations and your detailed explanation, I |
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Re: newbie inquiry: what kills
dragnfyr
I had a brother who was struck directly by lightning, had the scars on his
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head and foot where it went in and out till his dieing day... also worked with someone who took enough charge to burn off a finger on each hand and blow himself out of the bucket on our truck... he lived as well (although they say its only because he hit flat on his back and that restarted his heart) Drag -----Original Message-----
From: Keith Messent [mailto:rkmessent@...] Sent: Tuesday, October 30, 2001 11:28 PM To: Electronics_101@... Subject: Re: [Electronics_101] Re: newbie inquiry:what kills I think that there is a difference between those who have been struck directly by a lightning flash (now deceased!) and those who have been in the close vicinity of a strike! I find it just about impossible to allow that anyone directly struck and burned by a discharge could possibly survive. As I reported earlier, it is generally accepted by Health & Safety authorities that 10 Joules (via PD >230V) through a vital organ would be lethal! Keith Messent, Skipton, UK ----- Original Message ----- From: <adityanewalkar@...> To: <Electronics_101@...> Sent: Wednesday, 31 October, 2001 07:17 AM Subject: [Electronics_101] Re: newbie inquiry:what kills Think about lightning. Lightning has millions (10^6) of amperes of To unsubscribe from this group, send an email to: Electronics_101-unsubscribe@... Your use of Yahoo! Groups is subject to |
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Re: International agreement on allocation of frequencies.
Himanshu Sharma
Not exactly....each use its own...and have some common understandings...
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Like we may use some wave-length for some transmission and some other country may use it for some-other...but they both use all the frequencies... Hope that I am correct... Regards :-), --himanshu sharma ----- Original Message -----
From: angtengchat <angtengchat@...> To: <Electronics_101@...> Sent: Thursday, November 01, 2001 6:34 AM Subject: [Electronics_101] International agreement on allocation of frequencies. : ----- Original Message ----- : From: "Jim Purcell" <jpurcell@...> : : > Well, there are two factors, what the modulation : > frequencies the transmitter is capable of and what : > bandwidth the FCC allows. Both are +/- 15 kHz in : > most cases. How can this be, simple, stations are : > never assigned frequencies close enough to interfere. : > You won't have one station at 1000 kHz and a near : > by one at 1010 kHz or 990 kHz, and probably none : > at 1020 or 980. : > Jim : : Is there an international agreement whereby each radio / tv station from : different countries are allocated certain frequencies so that they would not : "clash" with each other? : : Thanks : : : _________________________________________________________ : Do You Yahoo!? : Get your free @yahoo.com address at : : |
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Re: Energy
Himanshu Sharma
Hey,
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The best option is the Hydrogen Energy...(We make controllable Nuclear Fusion Reactors and we are through...)And as far as the studies show we are very near to it....So energy won't be a problem... So be happy and forget about this problem a little...Just think that how will we take the energy to the Vehicles and other movables..... Regards :-), --himanshu sharma ----- Original Message -----
From: angtengchat <angtengchat@...> To: <Electronics_101@...> Sent: Thursday, November 01, 2001 12:50 PM Subject: [Electronics_101] Energy : As oil / energy is scarce, it would be great if we could find an : "alternative source of energy" before oil gets depleted in about 200 - 300 : yrs from now. : : I'm fully aware of that theory of concervancy of energy. : : Therefore, I would appreciate if someone here could teach / tell us how : energy could be tap from the sky (solar energy) or some other sources. : : Thanks. : : : : : _________________________________________________________ : Do You Yahoo!? : Get your free @yahoo.com address at : : |
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Re: Bomb
angtengchat wrote:
To understand how bomb works IS an electronic question. We have things????????? For those of you who do not know Who I am, I am the owner of this list. This subject is OFF TOPIC. I don't think I can make things any more clearer here. This topic is closed. There are young members on this group, I do not wish them to think that it is necasary to know this sort of information. I have stated before that??? I am not for censorship in any form. However I do not consider this subject suitable material for this forum. We have already lost at least one member becuase of this topic, and I personally feel this is one too many, regardless of how many posts they may have made. ????????? I hope that this will end the discusion and I will not have to take further action. ??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O( ???????????? The Sinister Dragon ??? Hey, Just because I'm EVIL, ???????????? Doesn't make me a bad person......????????? >:-) ??? |
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Re: CPU question
Well there is one more thing that can be done with old
PC's - while we are at the subject. Old PC's can be combined to make a super computer. The idea and technique are those of the Bewoulf Cluster Computing. Incase somebody wants a starter on this they can get a very good article from the Scientific American Website where three chaps from Oak Ridge National Laboratory got together to build a super computer using old 486's and Pentium computers. -Saad --- Doug Hale <doughale@...> wrote: It is doable. There are many companies out there __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. |
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Energy
angtengchat
As oil / energy is scarce, it would be great if we could find an
"alternative source of energy" before oil gets depleted in about 200 - 300 yrs from now. I'm fully aware of that theory of concervancy of energy. Therefore, I would appreciate if someone here could teach / tell us how energy could be tap from the sky (solar energy) or some other sources. Thanks. _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at |
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Energy
Keith Messent
Use of fossil ('mineral') oils usually results in the ultimate
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production of carbon dioxide which ends up in the atmosphere. The only effective means of depleting the atmosphere of carbon dioxide is by photobio-synthesis of sugars (and via bio-chemical pathways within living organisms to other complex organic substances, including fats and oils). When the supplies of mineral oils in the world have been depleted to the point where it it would be uneconomic to try and extract more, perhaps the salvation of the Human species will come to rely upon oils derived a) from uni-plast micro-organisms like yeasts, and b) essences expressed from renewable resource higher plants ('essential' oils). The energy for both syntheses comes, of course, from the Sun (provided this source is not blocked by thick cloud of whatever earthly origin and continues to wander through the Milky Way free from celestial collision with some other body, which would be the end of everything!). The technology probably already exists, or could be adapted from known technology, whereby sufficient oils for lubrication purposes could be produced to satisfy world needs! Whether sufficient oil for fuel purposes could ever be produced this way may be debatable, but at least technology has already come up with a variety of renewable and environmentally friendly resources which could keep humanity going until some genius comes up with a better way of generating power. Perhaps we should be looking with more interest at the living organisms which are independent of direct sunlight! I refer to the bathysperic bacteria and other deep-sea organisms of the volcanic 'smokers' of the mid-Atlantic ridges. Keith Messent, Skipton, UK ----- Original Message -----
From: Himanshu Sharma <hs_ramdev@...> To: <Electronics_101@...> Sent: Thursday, 01 November, 2001 10:28 AM Subject: Re: [Electronics_101] Energy Hey,we are very near to it....So energy won't be a problem... |
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Re: PIC resources
Teodoro M. Villamarzo
Sorry for this newbie question, but I'm really interested:
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Can some tell me what a PIC is, and what it does, and what the differences between the PIC17 and 18? Thanks... Ted At 08:48 PM 10/30/01 -0500, you wrote: Must agree, 18 is way better than 17. Hopefully soon they'll get all |
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