Post by thread:electronics education (was Horrible Newbie...)

>Where do I get a quick practical self taught electronics education? I did it in this order: "Teach Yourself Electricity and Electronics" (The Hamburger Book) Stan Gibilisco, Tab Books (McGraw Hill) ISBN 0-8306-4133-5. Takes you from Atoms, to RLC, and Digital Principals. Complete with tests at every chapter/ Midterm and final. More than an introduction. It tool me 6 months to finish the book but it was worth the struggle. Freshman college level text, you had better remember graph theory and that 1/sqrt(-1) = sqrt(-1) for RL, RC, RLC "Electronics, A Systems Approach" Neil Storey Addison-Wesley ISBN 0-201-17558-4. This book is how to build systems with the information you've just learned. Alot of practical approximations. heavy on opamps/ fet/ BiPolar. Don Lancaster's "TTL/CMOS Cookbooks" Hard to find but not impossible. classic texts. Alot of overlap as most devices come in ttl/cmos flavors. "CMOS/TTL Digital Systems Design" James Buchanan, McGraw Hill ISBN: 0-07-008711-3. Into the frying pan! covers Noise, transient currents, power distribution, synchronous design, clock distribution, signal interconnection, signal quality, system timing, and reset signals . a real eye opener. Then Pick up a copy of "The Art of Electronics" by Horowitz and Hill. 2nd Edition. It will drive home much of the above but from a different perspective. as far as a "QUICK" education... expect to spend 6 months to a year with the above material, and alot of time at the bench. Get a comfortable stool! I'd like to find a good Systems Level book on designing WITHOUT IC's. Something like the Vol 1-5 of "Circuits you'll never use :-)" that focuses on HOW to work magic with a handful of resistors/caps/transistors/and diodes. any recommendations? mjps_

At 12:52 PM 6/6/97 EST, you wrote: >> From: Mike Schreck <schreckKILLspamHORIZSYS.COM> >>[cut] >> remember graph theory and that 1/sqrt(-1) = sqrt(-1) for RL, RC, RLC > >Please explain -- in normal complex mathematics 1/i = -i. mmmmm ! If i=sqrt(-1) then i^2=-1 so by substitution, 1/i = -(-1)/i = -i^2/i = -i So 1/sqrt(-1) <> sqrt(-1) but 1/sqrt(-1) = -sqrt(-1) Rgds Mike Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. Massen

At 04:34 AM 6/6/97 +0800, you wrote: >Steve Hardy wrote: >> >> > From: Mike Schreck <.....schreckKILLspam.....HORIZSYS.COM> >> >[cut] >> > remember graph theory and that 1/sqrt(-1) = sqrt(-1) for RL, RC, RLC >> >> Please explain -- in normal complex mathematics 1/i = -i. >> >> Regards, >> SJH >> Canberra, Australia >Who your mean (high school). >B.R. > Saras Hey saras - first one is wrong, the last one is correct 1/i = -i !! Rgds Mike Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. Massen

Or, i * 1/i = 1 => i * i * 1/i = i => -1/i = i => 1/i = -i {Quote hidden}> > If i=sqrt(-1) then i^2=-1 so by substitution, > > 1/i = -(-1)/i > > = -i^2/i > > = -i > > So 1/sqrt(-1) <> sqrt(-1) but 1/sqrt(-1) = -sqrt(-1) > /*****************************************/ /* Matt Calder, Dept. of Statistics, CSU */ /* http://www.stat.colostate.edu/~calder */ /*****************************************/

On Fri, 6 Jun 1997, you wrote: > >Please explain -- in normal complex mathematics 1/i = -i. > > If i=sqrt(-1) then i^2=-1 so by substitution, Sorry to be a purist here, but the square root is not defined on negative numbers. Although the complex number i has the property i^2 = -1, that does not implicate that i = sqrt(-1). Even if this were a valid expression at all, i = -sqrt(-1) would have been an equally valid implication. At that point, i = -i would be a valid conclusion.. and 1 = 0 also. Cheers, Joost

At 01:01 AM 6/8/97 +0200, you wrote: >On Fri, 6 Jun 1997, you wrote: > >> >Please explain -- in normal complex mathematics 1/i = -i. >> >> If i=sqrt(-1) then i^2=-1 so by substitution, > >Sorry to be a purist here, but the square root is not defined on negative >numbers. Although the complex number i has the property i^2 = -1, that >does not implicate that i = sqrt(-1). Even if this were a valid >expression at all, i = -sqrt(-1) would have been an equally valid >implication. At that point, i = -i would be a valid conclusion.. and 1 = >0 also. Bollocks - there is no consistent mathematic proof that arrives at 1=0 or i=-i UNLESS you are inconsistent with your definitions OR apply them selectively. Note I said 'IF i=sqrt(-)' Sure sqrt of (-1) is not defined AS A RESULT - that is why we give it the value 'i' - because we do not have anything other than a symbolic understanding of the result. By giving i the value sqrt(-1) does not invalidate i^2. Check your definition of sqrt and square, last time I came across this it was valid for all SYMBOLS ! You are stepping into psuedo maths - the sort some people use to try and prove that Engineering is a branch of Devil worship etc Rgds Mike Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. Massen

> > >Please explain -- in normal complex mathematics 1/i = -i. > > If i=sqrt(-1) then i^2=-1 so by substitution, > Sorry to be a purist here, but the square root is not defined on negative > numbers. Although the complex number i has the property i^2 = -1, that > does not implicate that i = sqrt(-1). Even if this were a valid > expression at all, i = -sqrt(-1) would have been an equally valid > implication. At that point, i = -i would be a valid conclusion.. and 1 = > 0 also. > Joost Joost, I think you're right if you're talking about the arithmetic square root but I guess they were referring to the general square root that, BTW, has two answers and so you can't implicate something like i=-i . . . Regards, Andres EraseMEadjordjspam_OUTTakeThisOuTaleph.fi.uba.ar

At 05:26 AM 6/8/97 +0000, you wrote: >> > >Please explain -- in normal complex mathematics 1/i = -i. >> > If i=sqrt(-1) then i^2=-1 so by substitution, >> Sorry to be a purist here, but the square root is not defined on negative >> numbers. Although the complex number i has the property i^2 = -1, that >> does not implicate that i = sqrt(-1). Even if this were a valid >> expression at all, i = -sqrt(-1) would have been an equally valid >> implication. At that point, i = -i would be a valid conclusion.. and 1 = >> 0 also. >> Joost > >Joost, I think you're right if you're talking about the arithmetic square >root but I guess they were referring to the general square root that, >BTW, has two answers and so you can't implicate something like i=-i . . . Definitely NOT - he can't be right for arithmetic square root Andres !!! Take the example of sqrt(4) which has two possible solutions 2 OR -2. This does NOT (in any way) MEAN -2 = 2 <Cough splutter groan> ====================================== So moving on to the case of i. Sqrt(-1) also has two possible solutions i OR -i. Now lets check it (and apply maths consitently):- -i x -i = (-1)xi x (-1)xi = (-1)x(-1) x i x i = 1 x i^2 = i^2 And by definition i=sqrt(-1), so:- -i x -i = -1 Just because i x i = -1 is a possible solution, does not mean i = -i, just because the equate of -i x -i = i x i Care to check it with the number 2 ? -2 x -2 = 2 x 2 Which does NOT mean -2 = 2 (in the universe of which I am a participant) ! Therefore Joost is either nuts or should go back to high school... Rgds Mike A conclusion is a place where a person got tired of thinking.

>You are stepping into psuedo maths - the sort some people use to try >and prove that Engineering is a branch of Devil worship etc Aren't they? Andy ================================================================== Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 Hardware & Software for Industry & R/C Hobbies "Go fast, turn right, and keep the wet side down!" ==================================================================

At 08:47 AM 6/8/97 -0400, you wrote: >>You are stepping into psuedo maths - the sort some people use to try >>and prove that Engineering is a branch of Devil worship etc > >Aren't they? mmm - well magnetism was always looked on suspiciously by the church, and there was this german guy in 16th century who covered his body with drawn wire - waved a few odd shaped magnetics and dissappeared - eek! The Dusseldorf experiment perhaps ;) Cheers Mike, Still in Perth, Western Australia "Angels are able to fly because they take themselves so lightly." -G.K. Chesterton PS: Anyone know if PICs (and micros in general have) an upper limit of operation on exposure to static magnetic fields.

> >Joost, I think you're right if you're talking about the arithmetic square > >root but I guess they were referring to the general square root that, > >BTW, has two answers and so you can't implicate something like i=-i . . . > Definitely NOT - he can't be right for arithmetic square root Andres !!! > Take the example of sqrt(4) which has two possible solutions 2 OR -2. > This does NOT (in any way) MEAN -2 = 2 <Cough splutter groan> That's what I'm talking about, but have in consideration that the root that has several results is the general root, the arithmetic root has only one solution that has to be a postive real number. At least is what I've learned. > Therefore Joost is either nuts or should go back to high school... Oops... Now that I think again, Joost has another point on his side, that is that if you're using an operator like "sqrt()" it's pretty obvious that you're talking about the arithmetic root because it would be odd to have a computer function return two values! And again, when we use the symbol we use for roots it is for the arithmetic one, the general root should have a different notation like putting the radicand between double parenthesis or writng an asterisk before it, so most of the times we talk about arithmetic roots unless stated. Regards, Andres Djordjalian adjordjspam_OUTaleph.fi.uba.ar

At 11:58 AM 6/8/97 -0400, you wrote: >PS: Anyone know if PICs (and micros in general have) an upper limit of >operation on exposure to static magnetic fields. They must. How about the force that a magnetic field produces on a current-carrying wire? If the field were _REALLY_ strong, it could pull the connections apart inside. Also, the Hall effect would cause parts of the chip to become polarized when they shouldn't be. The field would probably have to be rediculously strong! Sean

>PS: Anyone know if PICs (and micros in general have) an upper limit of >operation on exposure to static magnetic fields. I'll ask a buddy of mine who does EMS testing for NASA. (FWIW, some of the best PCMCIA ethernet cards turned out to be Xircom). Andy ================================================================== Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 Hardware & Software for Industry & R/C Hobbies "Go fast, turn right, and keep the wet side down!" ==================================================================

For all who were interested in magnetic susceptibility, this comes from a friend of mine who works for NASA's Johnson Space Center (aka "Houston" as in "we have a problem.") Andy > > >PS: Anyone know if PICs (and micros in general have) an upper limit of operation on exposure to static magnetic fields. Andy, I just spoke to our Portable Computer System (Space Station PC) folks and they told me that the EMI testing consists of blasts of radio frequencies over a broad spectrum. However, they do not do steady state magnetic susceptibility testing at all. As a matter of fact, they are under the impression that PC seem to "belly-up" when exposed to even moderate magnetic fields. I asked about exposure to degaussers and they said that they avoid that entirely because of potential damage to the units. On thing that comes to mind though is that when the Shuttle passes through the South Atlantic anomaly (essentially where the Van Allen belt converges into the atmosphere in the southern hemisphere, there are strange magnetic anomalies all over the place (compasses undergo wild swings, etc.). I don't have any data from flights regarding PC performance while passing through the area but I do know that about once a day, the PC's on the Shuttle do "lock-up" and have to have to be recycled. It is only a "soft" latch-up, not a "hard" or damaging the PC occurrence. While this might not be what you're seeking, it is an answer! Sorry I don't have a complete one for you. Talk to you later, Jimmy ================================================================== Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865 Hardware & Software for Industry & R/C Hobbies "Go fast, turn right, and keep the wet side down!" ==================================================================

> From: Sean Breheny <@spam@sbrehenyKILLspamCSRLINK.NET> > To: KILLspamPICLISTKILLspamMITVMA.MIT.EDU > Subject: Re: electronics education (was Horrible Newbie...) > Date: Monday, 9 June 1997 07:55 > > At 11:58 AM 6/8/97 -0400, you wrote: > > >PS: Anyone know if PICs (and micros in general have) an upper limit of > >operation on exposure to static magnetic fields. > > They must. How about the force that a magnetic field produces on a > current-carrying wire? If the field were _REALLY_ strong, it could pull the > connections apart inside. Also, the Hall effect would cause parts of the > chip to become polarized when they shouldn't be. The field would probably > have to be rediculously strong! Some are, f'rinstance, the superconducting magnets inside medical diagnostic equipment like MRI etc. I was reading a fire fighters journal about the kind of precautions that need to be taken inside these - WOW! And the hospital authorities are reluctant to 'dump' the field (understandable). Would shielding (mu-metal) help here? MikeS <RemoveMEmikesmith_ozTakeThisOuTrelaymail.net>