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Intro to electricity

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Intro to electricity Electricity I - Charge! Charge - as fundamental to electricity & magnetism as mass is to mechanics Charge is a concept used to quantatively related "particles" to other particles, in terms of how they affect each other - do they attract or repel?  If so, with what force? Charge is represented by letter Q. The basic idea - likes charges repel (- and -, or + and +) and opposite charges attract (+ and -). Charge is measured in units called coulombs (C).  A coulomb is a huge amount of charge, but a typical particle has a tiny amount of charge: - the charge of a proton is 1.6 x 10^-19 C.  Similarly, the charge of an electron is the same number, but negative, by definition (-1.6 x 10^-19 C).  The negative sign distinguishes particles from each other, in terms of whether or not they will attract or repel.  The actual sign is arbitrarily chosen. The charge of a neutron is 0 C, or neutral. But what IS charge? Charge is difficult to define. ...
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Magnetism, Electromagnetism, and EM Induction

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Magnetism! Similar to the case of charge, magnetic poles are divided into North and South poles. A North magnetic pole is one that points toward the Earth's magnetic north pole.  This means that the Earth's magnetic north is ACTUALLY A SOUTH POLE (magnetically speaking). Also: - Like poles repel - Opposite poles attract - Each magnet must have at least one North and one South pole (though they may have more than one of each).  There is NO such thing as a magnetic monopole. - Magnetic fields are real, but the lines are imaginary - Field lines indicate the direction that a compass needle would take in the vicinity of the magnetic field. - There are naturally occurring magnetic minerals - a very common one is called magnetite (Fe3 O4) Magnetic north on the Earth is near Ellesmere Island in Northern Canada, several hundred miles from true (geographic) North (the North Pole).  It is moving toward Russia at several miles per year. For gory detail: http://en.wikipedia.org/wiki...
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Circuits 1

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Thus far, we have only discussed "static" (stationary) charges.  Static charges alone are useful, but not nearly as much as charges in motion.  As you recall, electrons are the most easily moved particles.  However, for sake of ease in sign convention (positive vs. negative), we define the following: Current  (I) - the rate at which positive charge "flows" I = Q/t The unit is the coulomb per second, defined as an  ampere  (A).  Just as one coulomb is a huge amount of charge (nearly 6.3 billion billion protons), one ampere (or amp) is a tremendous amount of current - more than enough to kill a person.  In fact, you can feel as little as 0.01 A.  Typical currents in a circuit are on the order of mA (milliamperes). Essentially, current is how quickly charge travels (or charge per time, q/t).  The unit (a coulomb per second) is called the ampere (or amp, A).  To keep things simple, we think about positive charge moving, ...
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