Filename: TUTS/voltamps.tut -- Volts and Amps and Coulombs and Watts! Oh My!! ---------------------------------------------- A Tutorial in the Electrical Basics copyright (c) 1997 by Richard Steven Walz Free for Non-Commercial Distribution But: All Rights Reserved rstevew@armory.com http://www.armory.com/~rstevew/ ftp://ftp.armory.com:/pub/users/rstevew/ ----------------------------------------------------------- First you must understand the Coulomb. The Coulomb is 6.24E18 electrons. ------------------------------------------------------------------------ Boy, that needs some explaining for some folks! This is s.e.basics!! That's 6,240,000,000,000,000,000 electrons, where the zeros simply are to fill places of inaccuracy for approximation. Note there are 18 decimal places after the 6-point-whatever. The notation 6.24E18 means really the BASIC and FORTRAN and some calculator programming language ways of writing the scientific notation for 6.24 x (10 to the eighteenth power). This is written often as 6.24 x 10^18, since in text on the Net we can't write little raised up (superscript) exponents. That's a HELL of a "pile" of electrons, a quantity really, since they all repel each other and so wouldn't stay in a pile very well. At least not a BIG pile. Tiny piles are called "static electricity" because it's not flowing in a conductor. -Steve >Voltage in Volts is the amount of energy in Joules per Coulomb of charge. >This is what people often call the pressure. V=J/C ----------------------------------------------- Yeah, he's right, but he didn't quite tell you what a Joule was!!! A Joule is the energy of motion of a kilogram mass being accelerated by your hand and arm or by a rocket engine or a floppy heavy rubber baseball bat you have hit it with to a speed of 1 meter per second every second the force is acting on it for a distance of 1 meter!! Or any combo of such forces or such achieved speed through a distance that multiply out to 1 single little kilogram meter meter/second per second. The acceleration part is the meter per second per second, as in how many meters/second the force of whatever added to the kilogram in a second, and how far did that take! Surely if it took longer, then it wouldn't be as much, so we have to multiply and divide the mass, the distance per second, per second, and the distance it took to achieve that. The distance is the distance through which your hand and arm, or the rocket engine, or the rubber baseball bat is actually pushing it, and nothing counts after it leaves your hand, or the rocket engine stops or the baseball bat leaves contact with it. You are actually familiar with a Joule and don't even know it, because of a more commonly used term for the rate of delivery of Joules to a device, namely Joules per second, called Watts!! It doesn't matter HOW LONG you leave the light on, except for your electric bill, as far as Watts are calculated, because that's a measure of the instantaneous rate of energy ransfer per second, counted in simply Joules/second. Calories can be converted into Joules, since they too are pure energy. A Joule then is in (kg*m/s/s)*m's or kg*m^2/s^2 . -- Einstein and Mass *IS* Energy!: And even a mass's energy can be calculated, from A. Einstein's E=MC^2 . The amount of energy in a kilogram of mass is in Joules, and it is calculated like this: Energy (in Joules) = Mass( in Kilograms) times C^2, the speed of light squared, (in metric, that is, as are all these terms!). The speed of light is almost exactly 3 x 10^8 meters per second, so squared top and bottom is 9 x 10^16 (powers of the same base multiplied, add together, like 10^3 x 10^3 = 10^6 [thousand times a thousand equals a million!] ). And its labels get squared too, so it's 9 x 10^16 meters squared per seconds squared! That may seem hard to understand, but it all falls out into your hand in the equation, and you will find that it DOES make sense! Now: That means that 1 kilogram has 9 x 10^16 Joules in it!! That is: IF we could destroy the kilogram completely to energy, it would become THAT MANY JOULES OF LIGHT ENERGY or MOTION ENERGY of some other MASS! It could also be POTENTIAL ENERGY if it were used to lift something to some enormous height and then it stayed there till it was dropped! This happens in even a lighted MATCH!!! A very tiny amount of the energy-mass of the atoms in the burning mixture and paper or wood on the end of a match, if allowed to radiate heat and light but NOT lose any atoms, would have the same number of atoms, and they would weigh slightly less, because their binding energy was changed to light and heat!! In a nuclear bomb, even MORE of a small percentage of mass is changed to light and heat, and in fusion, in the Sun, its light and heat comes from a fairly enormous, but still a VERY tiny fraction of its total mass each second!! It amounts to many millions of tons, but the Sun is enormous! It will burn another 3 to 4 Billion years at more or less its current rate. If we took half a kilo of matter and half a kilo of anti-matter and put them together, though, then ALL the mass would be annihilated, and ALL the 9 x 10^16th Joules would be released! Starship Enterprise time!! Whew! That's 90,000,000,000,000,000 Joules! If you could slowly run a 100 Watt light bulb with it it would burn for 900,000 trillion seconds, (trillion equals 10^12 for the UK folks!). That's 2.85 Billion years, (Billion here is US 10^9 for UK folk). About as long as the history of any life existing on earth, and close to time for the Sun to die from now!!! -- Just 1 kilogram or 2.2 pounds, even of cannabis, but it would lose completely its other uses: rope, cloth, rubber, concrete, and whatever other claims people smoking it wish to make! Just teasing, I would STILL recommend smoking it to anyone! Gets your head working!! ;-> -Steve >Current in Amperes is the amount of flow of electrons in Coulombs past a >point per second of time. I=C/s > >When you have a source with a potential of V volts delivering I amperes >you have P Watts of power delivered. Watts of power is equal to energy in >Joules delivered per second of time. P=V*I=J/C*C/s=J/s --------------------------------------------------------------------- We can't really go mixing names of terms with their units of measure like that! Power(P) and Potential(V) and Current(I) are NOT the same as the unit factor labels we use for the Number of Watts, Volts, and Amps!! Now the Theory: Well, that's all correct, except the confusing math notation. Should be P=V*I=Number of (J/C)*(C/s)=J/s in Watts. Gotta keep the operator precedence straight or they wind up with J/C^2*s <> J/s !!! (<> means "is NOT equal to"!). I like to see things is base quantities, rather than the derived Joule, however. So P (power in Watts) = V*I = Number of {(kg*m^2)/(C*s^2) * C/s} = (kg*m*m*C)/(C*s*s*s) = kg*m^2/s^3 = (kg*m^2/s^2)/s = Number of Joules/second!! Where a Joule, as my demo above, is in m*[(kg*m/s)/s]!! This culminates a full relation of electrical units to mechanical units in the metric system of Physics! See how the Coulombs fall out since they have no base identity with energy!?? Neat, eh?! -- -Steve -- -Steve Walz rstevew AT armory.com http://www.armory.com/~rstevew/ -Lots of New FTP Electronics Stuff!! 900 Files/45 Dirs (Full Mirror ==> *) -Steve Walz rstevew armory.com ftp://ftp.armory.com:/pub/user/rstevew * Europe:(Italy) ftp://ftp.cised.unina.it:/pub/electronics/ftp.armory.com * Oz:.AU ftp://ftp.peninsula.apana.org.au:/pub/electronics/ftp.armory.com *