studiot

No, No and no again. Why do you insist on changing Einstein's stipulations? Any fool can change the experiment so that it fails. So what. And why do you not want to hear (follow) the logic behind what Einstein actually specified? And why do you not want to answer the simple question I asked you as to the location of the source of the lightning?

I'm sorry imatfaal, but your solution is not valid. Third time lucky? As a matter of interest when I asked some engineers awhile back they tried a brute force and ignorance method (let the computer try every combination and filter). One reported 164 sets of matching numbers another reported 150 but neither picked out the one and only correct one. other wrong possibilities include 768 * 142 = 109056 762 * 132 = 100584

Did Einstein have a clock specified in his train experiment? Please point me to the reference.

I'm happy to do some (easy) maths with you as a reasonable presentation for distortion in a transistor can be made without Fourier series. However I would appreciate more full answers as this means quite a bit of work and I need to get the level correct. Here is a start, tell me if we can continue. First I will simplify my original equation by dropping the phase part. Also since I am considering specifically transistors my transfer function will be written in terms of an input voltage and a resultant output (collector) current. That is at any instant the collector current will be Ic = f(Vi) So consider a signal Vi= Vmsin(wt) , input to the transistor. If the transistor were linear then the output would be a first order or linear function of the input That is Ic = Iq + aVi Where the instantaneous output (collector current) equals a constant current (Iq) plus a variable current proportional to the instantaneous input voltage. (The constant current is called the bias or quiescent currrent of the transistor) a is the constant of proportionality called the transfer coefficient. So Ic = Iq + aVmsin(wt) So for linear operation the output is the input multiplied by a constant of proportionality. So there is no distortion. Now I showed the transfer curve curling over for non linear operation. The simplest such curve is second order or a parabola so let us assume that Ic = Iq + aVi + b(Vs)2 = Iq + aVmsin(wt) + b(Vmsin(wt))2 Where b is a second constant to be evaluated. = Iq + aVmsin(wt) + b(Vm)2sin2(wt) Since sin2(wt) = 1/2(1-cos2wt) Ic = (Iq + b(Vm)2/2) + aVmsin(wt) - b(Vm)2/2 (cos2wt) So the output collector current consists of the following three components A DC component equal to (Iq + b(Vm)2/2) An alternating fundamental componenet of frequency equal to that of the driving frequency with a peak value equal to aVmsin(wt) An alternating second harmonic component of a frequency equal to twice that of the driving frequency and of a peak value equal to b(Vm)2/2 If you can follow this so far we can continue this simple analysis of the harmonic distortion.

Le Repteux, Atomic or other clocks are irrelevent. Time measurement is not needed in Einstein's train experiment. So if we can stick to the original experiment details please, I will make the same offer I made to Robin in post#79 It really is very simple if you note down the correct sequence of events, without missing any out.

I don't understand the inconsistencies of the forum clock and find it a positive nusisance at times. For instance when I am replying in a thread and the poster I am replying to is noted as being online, I might expedite my reply for their benefit. Then I find that going back to the index/menus the poster was actually recorded as being offline a significant time before I posted so my rush was needless. Now I see the ridiculous situation where the poster of post#97 in this thread http://www.scienceforums.net/topic/85331-thought-experiments/page-5 Is recorded as being offline at 1.12pm although He is also recorded as posting at 1.14pm I wondered if this is to do with the fact that the thread is (partly) about time dilation?

Rectifiers will simply loose you half the signal Distortion can be filtered to some extent, but you would not want to do this at the power stage, further filters will also reduce wanted output. OK so you haven't yet done Fourier series. Do you understand feedback? I have roughed out some quick sketches to help. The first is a voltage transfer function, linear and non linear like a transistor or most amps. The second is what happens when you feed a pure sine wave into an amp with the non linear transfer function. You get a flattened sine wave out. You should plot for yourself a few points to see what happens. This is the best teaching aid.

Now we are getting somewhere. Your lecturer is correct. Think about a sine wave. This means that the instantaneous amplitude is continually varying and we have an instantaneous (voltage) amplitude Vinst = Vmaxsin (wt+p) I hope you understand this bit? So when the amplitude is say 0.25 volts the amplification factor is say 100. When the amplitude is say 0.5 volts the amplification factor drops to say 85 When the amplitude is say 0.75 volts the amplification factor drops even more to say 65. This means that different parts of even a simple sine wave are amplified by different amounts. So the result is not longer a true sine wave. I don't know if you have come across Fourier or Harmonic analysis yet? But essentially any continuous waveform can be expanded in a trigonometric series called a Fourier series. The original sine wave had only one term in this series - the fundamental. Harmonic distortion introduces additional terms which describe the distorted waveshape. So another description of harmonic distortion is that it introduces frequencies not present in the original.

One manufacturer used to call the perfect amplifier as "A piece of straight wire with gain". What did your lecturer say about distortion, of any type?

Glad you have the interest. You will certainly need to know all this before the end of an electrical engineering course. The more information about where you are coming from or your interest in a question the better will be the forthcoming answer. I was expecting further questions about my initial response.

Note I didn't say they were always present. Is this homework ie have you been asked to find out a list of distortions? I would look at Crossover distortion Intermodulation distortion Phase distortion Transient intermodulation distortion Other unwanted signals include Noise Hum Interference Other unwanted effects include Pumping/ motorboating Limiting/ clipping Inaccurate pre-emphasis/de-emphasis

Harmonic distortion occurs because the amplitude transfer function is (hopefully only slightly) non linear. The standard design method of reduction is to attempt to make the basic amplifier as linear as possible and then apply negative feedback. The user's method is to operate the amplifier with the volume at around the 45% to 75% of maximum. You should be aware that there are other types of distortion that are may need other countermeasures.

This problem kept me quiet for a couple of hours with a paper and pencil, the first time I did it Fill in the missing digits marked X Note that none of the Xs are a 7 and that the substituting digits must appear in the places shown. Since folks are just going to look up answers I will not attribute it for the moment.

No, but there are some that show exclusively one or the other such as the direction of refraction (wave). http://www.physicsclassroom.com/class/refrn/Lesson-1/The-Direction-of-Bending or the photoelectric effect (particle) http://en.wikipedia.org/wiki/Photoelectric_effect You should note that Schrodinger's equation is not strictly a wave equation at all, so quantum explanations need not suffer the demarcation.

I have already noted that this thread is chasing its tail because folks keep proposing alternative experiments before concluding the one in hand. If you wish to discuss Einstein's train then fine.

Quite frankly I don't see the relevance to the topic of this thread. Again I can't see the relevance of scale, although SR acts macroscopic scales. Further if it is fundamental it doesn't matter whether it is a usual or unusual application does it? You seem to be dancing away from the point and I don't know why since I am not disagreeing with you (not agreeing either) I'm only trying to clarify. You may like to know that the two properties I listed are considered equivalent to Einsteins first SR postulate.

Question 1) Do University Professors prefer the use of the words Please and Thank You, or their equivalent? Question 2) In a knockout tennis tournement there are n contestants. How many matches need to be played to determine the winner?

I don't know, because I'm not quite sure what you mean. Why do you need to qualify what you 'take for granted'? Incidentally did you read this comment I made to Christopher including a reference to your own posts?

Yes I understand one man is knocked down and killed on our roads every 4.3 seconds. I also understand that he is getting mighty fed up about it.

This thread is going nowhere at approximately 0.99999999999c because no one seems to want to stick to the point and complete discussion of the first proposed 'experiment', rather prefering to introduce alternative experiments. Comstocks experiment or Einsteins? I could just as easily observe that Einstein introduced the formula E = mc2 in 1905, some 24 years after JJ Thompson introduced the formula E = 0.75melmc2

So why didn't you comment then? I only offered two principles.

Christopher, Einstein's description has rather more hidden depths than perhaps you have given him credit for. It avoids the obvious trap that Robin's proposed alternative experiment falls into and that Le Repteux (rightly) objects to. Namely that you do not and should not try to arrange an experiment that requires a trigger, since information cannot travel faster than c. Einstein does not (as far as I am aware) explicity state this, but what he does state circumvents the issue in two ways. The reader is meant to work these out for himself. Firstly the lightning event is a chance event and by chance, happens just right for the experiment. Secondly matters can be confirmed at leisure post event.That is both the positions of the observers and strikes can be measured subsequently. Now ask yourself where does the lightning come from? Does it come from a universe moving alongside the train? Or does it come from the universe where the track is sited? Or does it come from another universe altogether? Please ask any questions you need to clarify my comments and answer the question (three choices) I have asked at the end. Using that answer I can explain Einstein's train experiment to you.

Your thesis? This is a discussion forum. I did not understand what you were posting so I asked for more information. That is the way discussion works. By contrast you say (now) that you did not understand what I said (fair enough) but you did not ask for more information, but instead made dismssive comments using 'my thesis', to ploughi on as if I had made no comment at all.

Le Repteux I am at a complete loss to understand how your post#71 was a reply to my post#67, as the quote would suggest. By fundamental I was thinking principles like:- The assumption that Space is isotropic (or not) The assumption that Space is homogeneous (or not) I can't see how measuring things with light or not measuring them this way is relevent or more fundamental. Personally I always measure space in glogs where 1 glog = 1.732/pi metres. So come on, what principles of Physics are you desireous of keeping and what are you willing to give up?

I see Google also identified maskinnik dot Kom. domain.