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Whats The Wattage In Bkk?


ironwolf

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Is the wattage in BKK is it 220 or 110?

It varies. In my house I have some 60W light bulbs, but recenly changed to flourocent bulbs that only takes 11W. My fridge takes a hel_l of a lot more, but my toothbrush runs on batteries - no idea what the wattage is there, peanuts I guess....

I'll be checking the currents over the weekend, and come back with a full report on the Amps on Monday. Have a nice weekend!

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OHM'S LAW

Resistance, R = Voltage/ Current = [ohm]

Current, I = Voltage/Resistance = [ampere]

Voltage, V = Current x Resistance =volt]

I = E/R

where I = Power, E = Voltage, R = resistance where Voltage & resistance are the known factors.

Edited by mijan24
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Correction I = E/R  :o

Power = E * I

Power = E^2 / R

Power = I^2 * R

To those who are not a United States Americans, the International System of Units may be more familiar.

A is the symbol for “ampere” (SI basic unit)

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per metre of length.

W is the symbol for “watt” (SI derived unit: W = J/s)

power

V is the symbol for “volt” (SI derived unit: V = W/A)

tension (voltage), potential difference, electromotive force

J is the symbol for “joule”

s is the symbol for “second”

SI is the abbreviation of “Système International”

I thought I’d make that clear, after reading about the space rocket blowing up, the one to put a satellite into orbit around Mars or something like that, because at NASA one group of scientists used inches and another group used centimetres. And that's no joke!

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Power is defined at the the derivative of Energy with respect to time (dE/dt). You can calculate the power by first calculating the energy in terms of voltage and current. So, must first define voltage and current.

Voltage between a point in space, A, to a point in space, C, is the path integral over the electric field between those two points. If the field is conservative (the curl of the E-field is 0), then the integral is path independent.

The electric field at a point anywhere in space is defined as the force per unit charge on an infintesimal test charge at that point in space.

Current is the rate of change, q, passing through a point with respect to time = dq/dt.

So, E = (Path integral of the Force per unit charge from A to C ) * q

P = dE/dt = d((Path integral of the force per unit charge from A to C ) * q)/dt

= (Path integral of the force per unit charge from A to C ) * dq/dt

= (Path integral of the electric field from A to C ) * dq/dt

= V * I (voltage times current)

Edited by quadricorrelator
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I thought I’d make that clear, after reading about the space rocket blowing up, the one to put a satellite into orbit around Mars or something like that, because at NASA one group of scientists used inches and another group used centimetres. And that's no joke!

Was not aware of this particular incident but do not doubt it for one instance. Have read many times over the years about SNAFU's caused through non-commanality of units of supply.

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Now could somebody please explain Ohm's Law. :o  :D

I will try to explain the intuitive idea behind Ohm's law. I will use an analogy first.

Suppose you had a pipe with water running through it. A greater volume of water will flow through the pipe per second if there is a greater pressure difference across the ends of the pipe.

You can think of the pressure difference across the pipe as the voltage being applied across your appliance. You can think of the water flow rate as the current. In an electrical circuit, it is electrons that flow (not water).

So, if you double the water pressure difference, then the water flow rate doubles. That makes intuitive sense. And, if the voltage across a circuit doubles, then the current (electron flow rate) also doubles.

The purpose of this explanation was to give an intuitive idea of the meaning of voltage and current, by using an analogy.

If you understand the idea of voltage and current, then you can go a step further. Let's do this by asking the question, "Given a pressure difference across a pipe, what is the water flow rate?" The answer depends on the diameter of the pipe, and the kind of obstructions inside the pipe. You need a greater pressure difference to achieve the same water flow rate for a given obstruction level. The ratio of pressure difference to water flow rate is a measure of the obstruction level. A lower ratio means that you need less water pressure difference to get the same flow rate. This means there is less obstruction.

You can think of electrical obstruction as analogous to the physical obstruction in a water pipe. The ratio of voltage across the appliance, to the current flowing through the appliance is the electrical obstruction level. Normally, the electrical obstruction level is called resistance.

You can state this in symbolic terms by saying that the V/I = R

V = The voltage difference across the appliance

I = The charge flow rate or current through the appliance

R = The resistance, or level of electrical obstruction

This formula is Ohm's Law.

I want to mention one qualification about this formula. This formula is only true if the resistance, (electrical level of obstruction) is both linear and memoryless. Some common electrical components, such as a capacitor or inductor, are not memoryless. Others, such as a diode are not linear (or memoryless). If the device is linear and memoryless, then it is called a resistor. Many household appliances (such as a light bulb, or an iron) behave as resistors, so you can safely apply Ohm's law.

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amazing...finally we learn something in this forum...just waiting for some lectures on quantum physics and Goedel's incompleteness theorems...Also the concept of "god" is not yet 100% clear to me. :D

I might even stop Yank-bashing for a while if I a get a sufficient answer... :o

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amazing...finally we learn something in this forum...just waiting for some lectures on quantum physics and Goedel's incompleteness theorems...Also the concept of "god" is not yet 100% clear to me. :D

I might even stop Yank-bashing for a while if I a get a sufficient answer...  :o

May I mention a little bit about Godel's Theorems? There is a famous Completeness Theorem, and a famous Incompleteness Theorem. The Incompleteness Theorem shook the foundations of Mathematics when it was presented.

I will try to explain the statement of the Incompleteness Theorem (we can discuss the Completeness Theorem later, but it less dramatic and more difficult to explain in my opinion).

One version of the Incompleteness Theorem states that there are mathematical statements which are true, but we can never prove them using the existing commonly accepted assumptions made within mathematics.

I have to define what is meant by "true" and what is meant by "provable" for this to make sense. I have to explain how a statement can be true without being provable.

Let me give an example of a statement which may or may not be true: "The sum of the first odd numbers is a perfect square." We can test a few examples of this statement.

1 + 3 = 4 = 2 *2 which is 2 squared - a perfect square

1 + 3 + 5 = 9 = 3 *3 which is 3 squared - a perfect square

1 + 3 +5 + 7 = 16 = 4 * 4 which is 4 squared - a perfect square

It seems like this statement might be true because it is true for the first three case, but we haven't tested every case. We can't test every case because the list of cases to test is infinite. If we thought we had tested every case, there would always be more left to test.

But, the statement could still be true. We just don't know if it is true using this method of testing.

We might be able to use the basic assumptions in mathematics and construct a proof of this statement from the assumptions. In fact, it is possible to do construct such a proof for this statement (one method is to use the principle of induction).

But, maybe there are some statements which seem true, but we can't test them, and we can't find a proof for such a statement. Godel showed that there are statements which are true, but we can never prove them.

There are two concepts here. One concept is whether or not the statement is true. The other concept is whether or not the statement can be proved from basic mathematical assumptions. It is possible to have one (truth of a statement) without the other (being able to prove it).

What's worse is this: If, somehow, we discovered one of these statements, and then added this statement to our list of basic mathematical assumptions, it still would not solve the problem. There would still unprovable, but true statements within mathematics. In fact, you can not find a finite list of assumptions from which all true statements can be proven (Mathematics can not be finitely axiomatized).

Let me back up a little bit. Mathematics starts with certain assumptions. In fact, the assumptions can be broken into the assumptions of Logic, and the assumptions of Set Theory. All of mathematics (algebra, calculus, topology, differential equations, geometry, etc.) has been developed from these assumptions. But, it is a finite number of assumptions. It is impossible to prove all true statements from any finite list of axioms according to Godel's Theorem.

Unfortunately, the bad news does not end here. It gets worse. No one knows if the basics axioms of mathematics (the logical axioms added to the set theory axioms) are even consistent. By inconsistency I mean the following: It is possible that we can derive a formula and and its opposite using the basic assumptions of mathematics (the ones accepted by mathematicians). It is possible we can prove that a formula is true, but also find another proof that the formula is false using the same universally accepted assumptions.

We just don't know if our assumptions are consistent. And, it even gets worse. Godel showed that we can never show consistency of these assumptions. So we don't know if the assumptions are consistent, and we can't ever know.

All statements within the framework of commonly accepted axioms of logic and set theory, may be based on a inconsistent assumptions.

The consequence of inconsistent assumptions is complete disaster. Within inconsistent systems, you can prove that every formula is true. The system is meaningless (incidentally, this notion of inconsistency resolves some of the paradoxes such as God being able to "create a rock so heavy that even he can't lift it". The assumption of total omnipotence is inconsistent. The assumption of total omniscience eliminates free will).

The completeness theorem is less dramatic and is actually quite good news.

Edited by quadricorrelator
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I'm baffled...ok...no yank-bashing from my side for the next seven days. Will drink Miller Light for chastisement.

So you (resp. Goedel) are suggesting that the whole mathematic is pointless? I somewhat sensed that already back in school...

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All statements within the framework of commonly accepted axioms of logic and set theory, may be based on a inconsistent assumptions.

The consequence of inconsistent assumptions is complete disaster.

Yorkie, are you using a second nick when your pissed ?

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I'm baffled...ok...no yank-bashing from my side for the next seven days. Will drink Miller Light for chastisement.

So you (resp. Goedel) are suggesting that the whole mathematic is pointless? I somewhat sensed that already back in school...

I think I understand your point. It seems like Godel's Theorem could lead to the conclusion that mathematics is pointless. You might think, "Why should we continue using these assumptions if we don't even know if they are consistent? All hope is lost if we know that we can never prove consistency."

Godel's Theorem was a great psychological blow to some of the leading mathematicians of the time. It was a terrible disappointment for them because they expected that all true statements were provable, and they wanted to prove them. Oddly enough, Godel did not think it should effect the mathematical spirit, or effect progress in mathematics.

An opposing viewpoint might be this: Although we don't know about assumption consistency, mathematics seems to have incredible predictive value in the real world. I don't know of a single case where it has failed. Although, this is still not a proof of consistency because we have not tried all cases (and never can).

Mathematics has great practical use and seems to be perfectly reliable, so that seems to give it some meaning.

A mathematician's point of view might be this: For some reason, most professional research mathematician's continue their work without worrying about these basic assumptions. It doesn't seem to effect their work, and they don't worry about it. Logicians and Set Theoreticians worry about it because it is their job, but not many others can afford to spend time thinking about it, or even learning much about it.

Incorrect Theories can still be useful viewpoint: Incorrect theories can still have value because they might still be approximately correct in many situations. These could be physical theories, personal theories (about relationships, about Thailand, etc.), religious theories, etc.

Example 1 -physical theories: Newton's theories of mechanics are wrong, but we don't notice the problem unless we are moving near the speed of light. It is still our most valuable (and probably our only) tool for understanding mechanical phenomena at low speeds.

Example 2 - personal theories: Theories we make up ourselves have value. We construct theories and make decisions based on those theories. We know the theories might be wrong, but we don't seem to know any other way to make decisions. My belief that "there are no guarantees in life" is an admission that our personal decisions (therefore our theories) might be wrong

Example 3 - religous theories: Some people assume/believe that god is all powerful. This is a useful, but inconsistent assumption. It is a useful assumption because it provides comfort, it may help their faith, and it may help their life. But, it is logically inconsistent.

Limits of Logic: If we use our brains to search for the truth, then we wind up relying on logic. This seems to be a limit of the human brain. The structure of logic may say more about the human brain, then it does about the truth. Logic is a human construct, not necessarily an absolute in the universe.

Logic seems like an absolute because we all agree on it. But, we all agree on it because our brains are all the same. There could be other ways to search for the truth which we can not comprehend or imagine because of our limited brain.

In fact, all logic is limited because it is based on unprovable assumptions (even without Godel this is true). How can an assumption based system claim to be absolute? But, (without non-human intervention of some kind), this is all we ever have.

Edited by quadricorrelator
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It is strange that you are discussing Godel. A few days before your first post I mentioned Godel in the Bedlam forum. I have a question for you. Are you sure that Godel showed that in an axiomatic system there would be statements that could be proven true and false? It was my understanding that what he proved was that in an axiomatic system there would be statements whose truth or falsity could not be determined....and that as a result of this there would be statements that are true but not proveably true as well as statements that are false but not proveably false.

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It is strange that you are discussing Godel.  A few days before your first post I mentioned Godel in the Bedlam forum.  I have a question for you.  Are you sure that Godel showed that in an axiomatic system there would be statements that could be proven true and false?  It was my understanding that what he proved was that in an axiomatic system there would be statements whose truth or falsity could not be determined....and that as a result of this there would be statements that are true but not proveably true as well as statements that are false but not proveably false.

As you mention, Godel did not prove the existence of any statement which could be deduced, and at the same time have its negation also deducible. As you state, one of his results is that there are true statements which are not provable.

I apologize if I gave the impression that such statements exist. If they did exist, then our system of mathematics would be inconsistent (that is the definition of inconsistent).

(You say, "there would be statements whose truth or falsity could not be determined". Are you refering to "decidability" of a logical system? A first order logical system is decidable if there is a decision procedure for determining if a formula is provable. If a system is not decidable then it is not complete.)

I was trying to say that it is impossible to prove the consistency of the basic axioms. This statement is independent of the idea of truth. It is only a statement regarding provability of formulas, so you don't need a definition of truth for this to make sense. The result is: There does not exist any formula (statements are actually less general than formulas, which is why I use "formula" instead of "statement" in the definition of consistency), which can be deduced, and also have its negation deducible from the basic axioms (the axioms of logic are formulas, the axioms of set theory are statements).

May I ask, what is the bedlam forum?

Edited by quadricorrelator
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Now could somebody please explain Ohm's Law. :o  :D

That one is a toughie but here's a handy way to remember sine/cosine/tangent formulas:

Sally Can Tell Oscar Has a Hard-On Always

Sine = opposite over hypotenuse

Cosine = adjacent over hypotenuse

Tangent = opposite over adjacent

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