Message #167171

[[5025]]

The next fundamental concept that you must learn is prefixes.  Here is a basic list of the SI prefixes.

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Note: This is not a list of all units.

Tera   10^12
Giga    10^9
Mega   10^6
Kilo      10^3
Milli      10^-3
Micro    10^-6
Nano     10^-9
Pico      10^-12

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Now, I must make this very clear at the beginning of the class.  AC stands for Alternating current, which means that the current level is a sinusoid, and DC stands for Direct current, which means that the current level stays constant.

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Sinusoid:



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Now, we will start with the concept called "current".  Current is the amount of Charge that passes through a wire in any given period of time (be careful not to mistake this with flux [the amount of a substance or field that passes through an area in a given period of time]).  In other words, Current, which is represented by the symbol "i" is equal to the derivative of Charge, which is represented by the symbol "q" with respect to time.

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If this equation is reversed, the Charge can be found to equal the integral of the current with respect to time.

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Alright, that is all we have for today.  Next time we will discuss Ohm's Law.