INDUCTOR
a passive type electrical component designed
to take advantage of this relationship by producing a much stronger magnetic field
than one that would be produced by a simple coil.
TYPES
ABOUT
Symbol of inductance is L.
Unit of inductance is Henry.
Inductance - the property of an electric circuit by which an electromotive force is induced in it as the result of changing magnetic flux
Electromagnet - temporary magnet production due to flow of electric current.
Electromagnetic induction - production process electric form magnet.
Fixed
Variable
Air core
Iron Core
Ferrite core
Core loss
CONSTRUCTION
An inductor is usually constructed as a coil of conducting material, typically
copper wire, wrapped around a core either of air or ferrous material.
Core materials with higher permeability than air confine the magnetic field
closely to the inductor, thereby increasing the inductance.
Inductors come in many
shapes.
Most are constructed as enamel coated wire wrapped around a ferrite with wire
exposed on the outside, while some enclose the wire completely in ferrite and are called shielded͛͘
Some inductors have an adjustable core, which enables changing of the
inductance.
Small inductors can be etched directly onto a printed board by laying out
the trace in a spiral pattern.
CIRCUIT WITH INDUCTIVE LOAD
CONNECTION
Inductors connected in parallel 
Inductors connected in series-parallel 
Inductors connected in series 
Electromagnetic induction
When a conductor is moved across a magnetic field so as to cut through the lines of
force (or flux, an electromotive force (e.m.f) is produced in the conductor.
If the conductor
forms part of a closed circuit then the e.m.f produced causes an electric current to flow round
the circuit.
Hence an e.m.f is induced in the conductor as a result of its movement across the
magnetic field͘ This effect is knoǁn a ͚electromagnetic induction͛͘
Faraday's Law
An induced e.m.f is setup whenever the magnetic field linking that circuit
changes
The magnitude of the induced e.m.f in any circuit is proportional to the rate of
change of the magnetic flux linking the circuit.
Mathematical relationship between the induced e.m.f and the network
Faraday noted that the e.m.f induced in a loop is proportional to the rate of change of
magnetic flux through it
Self-inductance and the induced e.m.f
Inductance is the name given to the property of a circuit whereby there is an e.m.f
induced into the circuit by change of flux linkages produced by a current change.
When the e.m.f is induced in the same circuit as that in which the current is changing,
the property is called self-inductance, L.
Induced e.m.f is the product of self-inductance and the rate of change in current 
The factors that influence inductance
A component called an inductor is used when the property of inductance is required in a
circuit. The basic form of an inductor is simply a coil of wire.
Factors which affect the inductance
The number of turns of wire (N) - more turns the higher the inductance
The cross-sectional area of the coil of wire (A) - the greater the cross-sectional area
the higher the inductance
The presence of magnetic core - when the coil is wound on an iron core, the same
current sets up a more concentrated magnetic field and the inductance is increased
The way turns are arranged - a short tick coil of wire has a higher inductance than
the along thin one.
RISE AND DECAY OF CURRENT
Refer to Figure 5 when switch in 'a' position͕ inductor connected to DC supply.
The current had not achieved maximum value immediately.
The current are going to
reach maximum value in a period of time that certain caused by production e.m.f
induced by inductor which always against the supply voltage.
In other words, the
currant of the circuit is rise delayed.
When switch is being transformed to position 'b'
inductor circuit had short circuit (no supply voltage). The current is not decrease continue to zero but take a time
that certain from maximum value until zero value. Refer to figure 6 which is shown the
exponential graph changing of current in inductor circuit.
TIME CONSTANT
Time constant - defines as time for current achieve maximum (IM) if this maintain the
early promotion rate current.
Time constant at rise of current
Practically, the current did not rise by regular. By graphically, it achieves 63.2% from
madžimum ǀalue ;point ͚B͛ in figure ϳͿ in time constant͘
In other ǁords͕ time constant͕
also defines as time for current of inductor achieve 63.2% from the maximum value.
Time constant at decay of current
In decay of current through an inductor, a method to find values of time constant same
as in rise of current through an inductor.
The differences are value of current decay
from maximum value (IM) to minimum (0), and and value 63.2% replaced with 36.8% which is
100% - 63.2%.
Energy stored in an inductor
An inductor possesses an ability to store energy. The energy stored, W in the magnetic
field of an inductor is given by:
CAPACITORS AND CAPACITANCE
ABOUT
A capacitor is an electrical device that is used to store electrical energy.
The unit of capacitance is Farad. The symbol of capacitance is C.
Capacitance is defined to be the amount of charge Q stored in between the two
plates for a potential difference or voltage V existing across the plates.
A capacitor has capacitance of one Farad when current charging of one Ampere
flows in one second.
This process causing a transferring of one volt in plates
potential.
The Farad unit is too large for practical as charge ratio to its potential difference.
uses.
Thus microfarad (ʅF) , nanofarad (nF) or Pico farad (pF) is used as a suitable
unit for capacitor:-
Microfarad (μF)
1μF = 1/1,000,000F = 10-6F
Nanofarad (nF)
1nF = 1/1,000,000,000 = 10-9
F
Microfarad (pF)
1pF = 1/1,000,000,000,000 = 10-12F
TYPES OF CAPACITORS
Fixed
Variable
Unpolarised
Mica
Ceramic
Film
Air-gap
Paper
Polarized
Aluminium
Tantalum
Trimmer
CAPACITOR CONSTRUCTION
In its most elementary state a capacitor consists of two metal plates separated by a
certain distance d, d, in between the plates lies a dielectric material with dielectric constant E=EoE,
where Eo is the dielectric of air.
The dielectric material allows for charge to accumulate between the capacitor plates.
Air (actually vacuum) has the lowest dielectric value of
Eo = 8.854 x 10-12 Farads/meter.
All other
materials have higher dielectric values, since they are higher in density and can therefore
accumulate more charge.
so that, the capacitance is related to the dielectric of the
material in between the plates, the square area of a plate and the distance between the plates
by the formula:
Clearly, the larger the area of the plate the more charge can be accumulated and hence
the larger the capacitance.
Also, note that as the distance d increases the Capacitance
decreases since the charge cannot be contained as 'densely' as before.
By applying a voltage to a capacitor and measuring the charge on the plates, the ratio of
the charge Q to the voltage V will give the capacitance value of the capacitor
as: C = Q/V this equation can also be re-arranged to give the more familiar formula for the
quantity of charge on the plates as: Q = C x V.
CAPACITOR EQUIVALENTS CIRCUIT
Capacitor connected in series 
Capacitor connected in parallel 
Capacitor connected in series-parallel 
CIRCUIT WITH CAPACITIVE LOAD
Mathematically, the capacitance of the device relates the voltage difference between
the plates and the charge accumulation associated with this voltage:
q(t)=CV(t)
Capacitors which obey the relationship of equation (1) are linear capacitors, since the
potential difference between the conductive surfaces is linearly linearly related to the charge on the surfaces.
Note that the charges on the right and left plate of the capacitor in Figure 5 are equal
and opposite.
Thus, if we increase the charge on one plate, the charge on the other plate must
decrease by the same amount.
This is consistent with our previous assumption electrical circuit
elements cannot accumulate charge, and current entering one terminal of a capacitor must
leave the other terminal of the capacitor.
current is defined as the time rate of change of charge, 
Elements related to capacitance
Electric field:
Area that surrounds the electric charge or charges system where the
increasing and decreasing of electric force exists.
Line of electric force:
A line of electric force is known as line or curve that pointed out from
positive charge (+) to negative charge (-) in a magnetic field.
Electric flux:
Known as amount of electric force line pointed out from positive charge (+)
to negative charge (-) in a magnetic field. Flux symbol is Ψ(phi).
Electric flux density (D):
Electric flux density is a measurement of electric flux that pass through a
unit of plate͛s area with a coincide angle͕ that is an area of ϭ meterϸ͘
The ratio between the charge of the capacitor and capacitor plates.
The symbol used is D.
D = Q/A
Electric field strength:
When two metal plates are charged and separated in a certain distance, a
potential difference will exists between the plates.
A force was also generated, known as electric force and the symbol is E. The
magnetic strength depends on the potential difference and distance
between plates.
E = V/D
Dielectric:
Insulator that is used between the two plates of a capacitance is known as
dielectric.
Electric field exists in the dielectric and the flux density depends on the types
of insulator used.
Absolute permittivity (E):
Permittivity is a capacitance or ability to store energy of a capacitor.
A force was also generated, known as electric force and the symbol. It
depends on the dielectric substance, and the symbol is ɸ.
E = D/E
Factor that effecting capacitance
surface area
the thickness of
dielectric
material between the plates
PROCESS DISCHARGING AND CHARGING OF CAPACITOR
Charging process in capacitor
Discharging process in capacitor
In initial state, a capacitor is uncharged (Vc = 0V).
When a capacitor start
charged, maximum current will be flowing (i = Imax).
The current would be decreased by
exponent, while voltage will be rising by exponent also.
This state will continue until full
state (steady) achieved.
In this full state, current had decreased to zero value, while
voltage increased until maximum value.
The capacitor is said in fully charge.
When capacitor fully charge and then switch being transformed to ͚b͕͛ discharge
process for capacitor will happen.
The time taken to recharge and fully discharge is
5 =CxR.