Wednesday, January 28, 2009

Your Pregnant Congratulations Wording

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SUMMARY OF CURRENT








  1. Definition of electric current:
    power call
    the movement of charges (electrons) inside a conductor.
    For if there is power in a conductor is necessary
    among

    ends there is a potential difference
    . ( The difference
    potential between two points on a driver
    can be defined as the work required to carry the load
    drive from one point to another).





The electrical current is measured by the intensity

current (I )

which is defined as the charge that passes through
section of a conductor per unit of time. It is measured in amperes

(A). If the direction of the intensity is constant, the current is called continuous


















I
= q / t
(if I = cte)







I

generator (battery
)



lineata



de conexión

e -

interruptor






receptor




The
electrons move through the circuit from the point
lower potential (pole - ) at higher
potential (pole +), although the direction of flow is
backwards.








  1. Concept
    resistance (R)
    :
    is a measure of the opposition
    offering a conductor to passage of current.
    is measured in ohms (W ).
    resistance depends on the nature of the conductor

    ( r = resistivity) and its

    geometric (length L, section S)

    R = r L / S
















  1. Ohm law for a resistor R





The
current intensity that flows through a
thread is directly proportional to the potential difference between its ends and
inversely proportional to a quality driver called resistance
equal electrical





  1. Association of resistors




a)
Serial
A
R
1
C
R 2 B
I
= common;
V AC +V CB =V AB ;
.
R = R 1 + R 2
.





b)
En paralelo
A
B
I
=
I 1
+
I 2
; AB V = common;









  1. Measures electrical quantities
    : To measure the intensity
    flowing through a circuit using the ammeter

    and placed in
    series, but instead to measure the potential
    differential between the terminals of a circuit element is used
    voltmeter and placed in parallel
    with the item.







  1. Generators:
    are the devices that provide the energy needed to
    maintain the potential difference between ends a
    driver, with the goal of electric current in the circuit
    permanent. The energy supplied by the generator to the
    unit charge passing through it
    is called electromotive force (emf) and is measured in volts.
    and
    = W / q
    .




The generators are associated
:



and 1
and 2



a)
Serial :
and and = 1 +
and 2
r = R
1 + r 2



R 1
R 2 and 1, R
1



b) In parallel

and
= and 1 = and 2



(for generators equal)



and 2, r
2




  1. receivers (eg engines)
    : are devices that consume electrical energy
    transforming it into another type of energy.
    The power consumed by a receiver unit load

    called force (emf) and is measured in volts and
    '
    = W' / q







  1. generalized Ohm's Law
    .
    If there
    external resistors, generators and motors
    is expressed by:











  1. Energy supplied or consumed by each circuit element:





  • E. produced by generators
    = W = and q = e
    I t



  • E. consumed by the generators
    I = W = 2
    rt



  • E.
    consumed by W = heat engines + Mechanical = I 2
    r 't + e ' t I



  • E.
    consumed by the external resistance R = W =
    2 R t









The energy consumed by the resistance usually emerges in
as heat (
Law Joule ):
as 1J = 0.24 cal
®

Q = 0.24
I
2 R t






  1. The power of each
    circuit element:

    calculated by dividing the work between the time:
    example:
    power produced by generators: P = W / t =
    and
    q / t =
    and
    I








  1. To calculate the potential difference between two points on a circuit
    :
    V A
    ± is _
    is '_
    SI R SI _ r _
    SI r' = V B




where A is the point
before the effect of the intensity