electric
current
today
I am posting
again the subject of physics. As for the
material that is an electrical
current. I'd just learned
An
electric current is the amount of electrical charge resulting from the movement of electrons, flowing through a point in an electric circuit per
unit time. [1] An electric
current can be measured in units
of Coulomb / second or amperes. [1] Examples of electric currents
in everyday life ranging
from very weak in
units mikroAmpere (\ mu A) as in the tissues of the body to a very strong current 1 -200 kiloAmpere
(kA) as occurs in lightning. [2] [3]
in most circuits of
direct current resistance can be
assumed to be a constant electric current is so
large current flowing in the circuit depends on the
voltage and resistance
in accordance with Ohm's law. [1 ]Electric current is one of the seven basic units in international units. [4] The international unit for electric current is the Ampere (A). [4] formally defined as a unit of Ampere constant current which, if maintained, will produce a force of 2 x 10 - 7 Newton / meter between two straight parallel conductors, the cross-sectional area that can be overlooked, within 1 meter of each other in a vacuum. [4]
For constant current, the current I in
amperes can be obtained by the equation
where I is the electric current, Q is
the electric charge, and t is the time (time).
While in general, the electric current flowing at any given time are: [6]
While in general, the electric current flowing at any given time are: [6]
To
determine the total amount of
charge transferred in the period
0 to t through
the integration of: [5]
In
accordance with the above equation, the electric current
is a scalar quantity because both the charge Q and time t is a scalar quantity. [5]
In many ways it is often portrayed electric current in a circuit using the
arrow keys, [5] one
of them as in the diagram above.
The arrows are not vectors and vector
operations do not need. [5] In the diagram above show the current flowing
through the two branches and flows out through two other
branches. Since the electric charge is conserved,
the total electric current that flows
out should be the same as the electric current flowing into [5] so 
Arrows indicate direction of flow only
flow along the conductor,
not the direction in space. [5]
Flow direction
In the diagram depicted arrows in the direction of movement of the flow of positively charged particles (positive charge) or called the conventional flow. [7] positive charge carriers will move from the positive pole of the battery toward the negative pole. [5] In fact, the charge carriers in an electrically conductive particles are negatively charged electrons are driven by the electric field to flow opposite direction to conventional current. [5] Unfortunately, for reasons of history, use the following convention: [5]
The arrows in the direction of the flow is described movement of charge carriers should be positive, despite the fact that the charge carriers are negatively charged and move in opposite directions. [5]
Such conventions can be used in most circumstances it can be assumed that the movement of positive charge carriers have the same effect with a negative charge carrier movement. [5]
In the diagram depicted arrows in the direction of movement of the flow of positively charged particles (positive charge) or called the conventional flow. [7] positive charge carriers will move from the positive pole of the battery toward the negative pole. [5] In fact, the charge carriers in an electrically conductive particles are negatively charged electrons are driven by the electric field to flow opposite direction to conventional current. [5] Unfortunately, for reasons of history, use the following convention: [5]
The arrows in the direction of the flow is described movement of charge carriers should be positive, despite the fact that the charge carriers are negatively charged and move in opposite directions. [5]
Such conventions can be used in most circumstances it can be assumed that the movement of positive charge carriers have the same effect with a negative charge carrier movement. [5]
current
density
Current density (English: current density) is the flow of charge in a given cross-sectional area at any point the conductor. [5] In SI, the current density has units of amperes per square meter (A/m2). [5]
Current density (English: current density) is the flow of charge in a given cross-sectional area at any point the conductor. [5] In SI, the current density has units of amperes per square meter (A/m2). [5]
where I is the current in the conductor, J is the current
density vector that has the same direction
with the velocity of the charge if the positive
charge and the
opposite direction if the
negative charge, and dA is a vector element
wide perpendicular to the elements. [5] If
the electrical current uniform
along the surface and parallel to dA then
J is also uniform
and parallel to dA
so the equation becomes:
[5]
Soo
where A is
the total cross-sectional area
and J is the current density in units of A / m
speed
of drift
When a conductor is not passed an electric current, the electrons in it moving randomly with no net movement in any direction as well. [5] Meanwhile, when an electric current flows through a conductor, the electrons keep moving randomly, but they tend to drift along the conductor in the opposite direction the electric field produces a flow of current. [5] the speed of drift (English: drift speed) in a conductor is small compared to the speed of random movement, which is between 10-5 and 10-4 m / s compared to about 106 m / s on a copper conductor.
When a conductor is not passed an electric current, the electrons in it moving randomly with no net movement in any direction as well. [5] Meanwhile, when an electric current flows through a conductor, the electrons keep moving randomly, but they tend to drift along the conductor in the opposite direction the electric field produces a flow of current. [5] the speed of drift (English: drift speed) in a conductor is small compared to the speed of random movement, which is between 10-5 and 10-4 m / s compared to about 106 m / s on a copper conductor.
