studiot

Well I don't often link to other discussion sites, and I only found that one because I needed to fix a mobile phone, that was apparantly out of battery. A replacement battery didn't fix it, so I looked for the ideas presented in that discussion concerning the charging circuitry and a loose ribbon cable. In the event there was no ribbon cable, the micro usb was firmly soldered onto the one piece mainboard. However disassembly and reassembly brought the old battery and system back to life. But it still did not like the replacement battery - allegedy the same type number. Interestingly when I tested the new and old batteries off load they both showefd 4.1 volts - a bit high for the nominal 3.7v. ~As I said there were many lesson for those who read the discussion, not least the need to keep Li-ion batteries topped up every few months. My usage of portable power tools is diminished these days and rather intermittent and I do find the discipline prolongs active life PAL for those who rember the dogfood adververts.

Following a mobile phone charging issue I came across this intriguing discussion thread on reviving dead batteries and or devices. It starts off with a phone but goes not to rechargeable tools (drill, chainsaws etc) https://www.ukworkshop.co.uk/threads/how-i-charged-an-old-removable-mobile-phone-battery.146855/ I'm sure we could all learn something from this, for example DeWalt device battery terminal

Very subtle. +1

Yes I agree they are the same construction with different notation. This is exactky what I mean by a plethora of notation.

You don't actually have to post in a thread to 'vote', which is why I originally responded as I did for I did not then know who it was. The mods can see who voted what, of course.

Here is a good (polite) way to contradict someone.

Here is an excerpt from the Times of India that contradicts your statement. The Times of India6 animals that live without a heart and still survive in...We usually think of the heart as something every animal needs– pumping blood, carrying oxygen, and keeping the body alive. It’s seen as one of the most essential organs. But nature often breaks the ru

Judging by this and your other recent threads you are following some scheme connecting formal logic and maths. Both disciplines suffer from a plethora of notation, this may help. If you wish to contradict someone, my expectation would be to follow the bald negation with a proper mathematical substantiation of your own claim.

There has been continued interest in this subject since the days of Cantor and Poincare. Here are a couple of recent papers. One note of interest is confirming that the 1 in the naturals is the same as the 1 in the reals or the integers for those who widh to be strictly pedantic. Realnum_RMJ-2015-45-3-737.pdf acampo-real.pdf

Yes all constructions of R are isomorphic, I think at the current count there are more than 10 different ones. The only real issue about this is do you include the number zero in the naturals ? I don't see the downvote as justified, so I have added a balancing +1

There's nothing transient about a whip antenna transmitting or receiving CW. I think you have misunderstood my intentions anyway. The OP has admitted that the circuit as show serves no useful purpose, and it is also unclear whether the resistors R1 and R2 are the battery internal series resistors or not. Either way the three resistors are the only way power can be dissipated by this circuit, ideal voltage sources dissipate zero power. Therefore the input power must equal the resistive dissipation in the three resistors and his defining equation is a figment. I have tried to widen the discussion to something that comes a little closer to the real world, by discussing load lines. The configuration is actually very important in the electrical power industry where it appears as the parallel connection of generators. When the sources are alternating there are phase and other changes to consider. Further Sherwood's description of the circuit he shows specifically states that Kirchoff is not obeyed at switchon, and explains why. Equally you say that Kirchoff's laws are obeyed at every point. A small issue here as one is a loop law, not a point law,

Kirchoff's laws are a very convenient fiction in a similar way to centrifugal force and other imaginary forces such as such as virtual work. They work in the right circumstances, in that they produce the same answer as calculations with models more aligned to physical reality. Here is a short extract from the late Professor Shercliff's excellent book 'Vector Fields' - Cambridge University Press. J A Shercliff was Dean of Engineering and Applied Maths at Warwick, after leafing a distinguished early career in Magento Hydro Dynamics at Cambridge, Oxford and the UKEA Sorry for the integrals, j is current and q is charge.

I asked you three questions but you only answered one of them. I asked all three for good reasons, because it is no use being clever with maths if you are either using the wrong model or do not properly understand the 'correct' model. That is why I asked if this is electrical engineering or mathematical modelling. It should be remembered that the electrical symbols you have employed refer to perfect or ideal components. So both voltage sources are ideal. Do you understand the significance of that ? Equally all three resistors are ideal. But what do you imagine R1 (10 ohms) , and R2 (20ohms) actually are ? An electrical engineer would immediately say they are the internal series resistances of real world sources. This makes a difference to how the circuit and the model operate. I also asked why would anyone connect two batteries like this. Well they wouldn't because neither 5 volt nor 10 volt batteries actually exist. But here is a real world electrical engineering situation where one might. We have a nominal 1.5 volt battery that is somewhat discharged to 1.4 volts and we wish to boost its performance by adding in parallel a smaller but fresh 1.5 cell we have in the cupboard. The resultant voltage will never reach 1.5 volts but will be greater than 1.4 volts, which may be sufficient for our purposes. For calculation purposes assume the larger, but discharged battery has an internal resistance of 0.1 ohms and the smaller fresh battery has an internal resistance of 0.2 ohms. Such a parallel combination of batteries would then be used to supply a load RL which would be R3 (30 ohms) in your model circuit. At this point I owe you an apology since I misread you initial post that sought a nonlinear programming approach and thought you meant a linear programming solution. In point of fact an electrical engineer could perform a linear programming exercise on my battery problem, based on load lines which in this case are indeed straight lines. By drawing or calculating a load line for each battery, a load line for the parallel combination can be deduced to find the terminal voltage and thus the currents flowing in the loops. It is necessary to understand the action of an ideal voltage source and the concept of its terminal voltage. Addendum You should be very wary of Kirchoff's Laws are they are actually a rather convenient fiction. This was known as the famous crisis in the history of electromagnetic theory and was resolved in Maxwell in the 1860s. Consider a single wire that is not connected in one end and explain why Kirchoff predicts that zero current can flow into and out of this wire. For without such current radio transmission would simply not work.

There is of course a perfectly satisfactory way of defining multiplication as the result of repeated addition, if subtraction is also allowed. What is more difficult to get round is multip[lication by a fraction. The completion or lack of it of the operation also dependes upon the domain you are working in. Addition is complete in the natural numbers, but subtraction is only compete in the integers. In any axiomatic system axioms are used to deduce or prove theorems. It may be posssible to substitute some or all theorems for axioms, so providing an different but equivalent set.

Surely this statement cannot be right. Say there are G axioms and axiom G is found to be provable from the other axioms A to F. Unless the proof of G is independent of one or more axioms, say B, how does this lead to an inconsistent set ?

If you want ordered pairs, you need the Cartesin product a A with itself. The pairing subsets in the product space then provide one way to define a relation.

You will also find Tare in many places today for instance on modern digitql scales. When making bread I put the mixing bowl on the scales and press the Tare function to 'zero things before adding the ingredients.

The for all is a problem, the for all physical even more so. Can two physical things occupy exactly the same space ? Is orientation important important ? Say I have two allegedly identical mirrors and I stand them side by side, one with the mirror face towards me the other with its back to me. If I shine a torch on them I will observe two totally different responses to my light.

This must surely depend upon your definition of identical ? I suggest the best way to approach this situation is a pragmatic one, like the definition of a point particle. "Identical for my specified purposes"

Yes I understand you can indeed light farts. There was also that Frenchman who could fart in tune. https://en.wikipedia.org/wiki/Le_P%C3%A9tomane

I agree with those currents, but here's the thing. The lead to a voltage at the junction of the 3 resistors of just over 6.8 volts. I am not sure if you are studying maths or electrical engineering ? But why would anyone connect up two batteries as your 'model' has shown ? What do you know about your model ? I am not at all convinced that your 'lazy' objective function correctly identifes the minimum heat dissipation in the three resistors. The actual values of the three currents varies with the voltage at the triple junction. I have prepared an Excel spreadsheet of the currents for each of the possible voltages 1 through 9 and plotted the result to find a minimum total power at just over 8 volts (not 6,8 as you have). These were calculated using the correct power formulae without fiddle factors.

I don't understand why this question is being set in a recreational thread ? This has led to repeated requests for clarification. It is just too vague The actual answer will depend upon your formulation since some axioms/definitions/properties may be inherited. If it is really about the Peano system, which is first order logic, then peano arithmetic with only addition is Godel decidable; peano arithmetic with both addition and multiplication is undecidable. Peano axioms also refer to axioms for the construction of the natural numbers, as opposed to their arithmetic. Good discussion of these mathematical matters can be found in Computability and Logic Boolos and Jeffrey Cambridge University Press Readings in the Philosophy of Science Feigl and Brodbeck Appleton-Century-Crofts New York

Whilst I agree that energy considerations will produce solvable solutions via the shakedown theorem, I don't agree with your energy loss formula. Energy is not 1/2 resistance times current squared. Power is resistance times current squared , not one half of that, Energy is power times time.

Don't let mine get together with yours then.

OK so since 1990. But note the Gogle AI then contradicts itself with the second sentence about the UK. Looking quickly in post 1990 textbooks Edexel in 2000 (High School advanced Level) had the ph spelling MCQs in Pharmaceutical Calculation (pharmacists professional exam) had ph for sulphur but the f spelling for sulfathiazole. Most post 200 pharmacy books prefer the f spelling. So I expect the amercanisation of English to continue, considering the great resource imbalance. Mine is a 1966 reprint.