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Now we would like to identify what is an electric current SO AN ELECTRIC CURRENT here is simply the
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rate of floor of electric charges through a conductor.
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A conductor here means something which conducts electricity something which allows the flow of electricity.
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As an example of conductor is copper or the aluminium key which is a good conductor of electricity it
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loves electricity.
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It passes the electricity.
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So here this one is our wire which is made of copper or aluminium or any conducting the material.
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So the electric current is the rate of flow of electric charges 0 it of flowing of electrical charges
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through the conductor.
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We can say also the electric current is the time rate of a change of a charge and this current electric
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cut is measured in Bear which is a scientist.
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Now in order to find the equation in the electric current Assembly the rate of flow of electric guitars
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Zi rate means that differentiation with respect to time okay.
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Of electric charges which is q q representing our electric.
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It was and it measured in column so ze current is d q of our DTA or the rate of a change of or the rate
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of flow of electric charges which is measured in column.
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With respect to Tool Time so one and beer is equivalent to Q which is the column oversee time which
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is second
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so from this equation we can say that Z Q or the electric charges is equal to the integration of the
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current D.T. from ze initial time t not to a anytime T.
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Okay so if we would like to find the Z electric charges at any time then we would integrate the current
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from the initial time to any time mode like so this is electric current current.
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All I hear is moving from ze as a positive to negative.
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So let's delete this one case.
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So to avoid confusion.
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So C is that here we have the positive and the negative the current the flows here from the positive
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and the going is rosy negative and so the other direction here is in this direction since ze current
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is moving OK.
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So ze positive to negative is the direction of the current we say that our current is from Boston to
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a negative but actually the flow of electrons is from negative to ze positive.
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Okay.
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The flow of this electron causes ze current.
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OK.
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So scientist would have or had chosen to select his either direction of current from positive to negative.
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This is what he would like to do.
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Okay.
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That is what is needed in electric current now.
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Electric Current has two main types.
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One of them is called the Z direct the current or the DC current that remains constant of time as an
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example of this ZIRP.
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The current duty is that here we are drawing is a current as a function of time Zi variation of current.
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With respect to time as an example of this Zi batteries are battery having a current which is gonna
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start to waste time which is this one.
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Ze current have one directional or either direction on correct which does not change or time.
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This we can say that this one is an ADC by Eric the current.
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Having only one light action this one is considered as ADC 2.
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Why.
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Because this one is always boasted remember that this part this one is zero from here any value here
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is considered as a positive.
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So the current actually it changes but it is always greater than zero.
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Okay zero or greater.
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It is a positive value.
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It has only one direction this one is another we've all dizzy full with rectification.
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This two waves are discussed in my own course for power electronics.
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But anyway the second type in order to understand ze difference is the alternating current or the AC
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current which is the source in our home.
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This one can vary sinus or jelly.
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What does it mean.
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It can be like this.
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This one is all this sine wave.
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This is Z and B your wave which appears in our supply on our AC supply.
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So see that here.
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During is this port ze current is varying but it has a positive value greater than zero.
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So it has a positive direction.
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In this case it has a negative value K so the direction of current is reversed here again positive value
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so positive negative positive negative so the current is alternating.
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It is changing with direction.
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Sometimes it is positive.
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Sometimes it is negative and so on.
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Another example is the square wave which appears in some kinds of inverters.
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Also I discuss this wave in the inverters of course.
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So it seems that it is sometimes a positive and go to negative positive negative positive negative.
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This wave is also an easy wave okay.
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So I have here some positive currents and which are having one direction.
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They don't change all the time as a direction not as a magnitude so as our direction is the same.
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So this means that we have a DC current AC current it means that our current is varying with time positive
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negative positive negative.
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So if we get back to our circuit to understand if we have a battery but there is concern that as a DC
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of supply DC supply means that our current is constant.
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We're having a on the direction so our current is always in this direction positive to negative.
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Now if we have an easy supply and the connected to a allude example our resistance so sometimes of course
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we represent our easy supply with this value or this sign.
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Sometimes the current will be here sometimes as high as the supply is positive negative so the current
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goes from here and sometimes the current reverses its popularity and that means that this one became
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a positive and the other one is negative.
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So this one is the positive and the negative.
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So in the negative cycle it moves in this direction.
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So the current is set to be alternating alternating between positive direction and negative direction.
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Okay.
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This in the case of a c supply.
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