PHYSICS Flashcards
Capacitors are used commonly and are useful as electronic
component in the modern circuits and devices. This has long history usage
of more than _____ years and was being studied, designed and developed up
to the present.
250
passive device for storing electric charges.
Capacitor
The simplest type of capacitor consists of two parallel conducting plates
separated from each other by a thin sheet of insulating material or ___________
dielectric
-
-
Each of these has advantages and disadvantages
based on _______, _____________, ___________
parallel-plate, spherical, and cylindrical.
capacitance, charge, and potential difference.
this type of capacitor has two parallel charging plates are separated by a dielectric that contains charges.
Parallel- plate capacitors
The capacitance that can be offered by a parallel-plate capacitor is ___________ to the area of the plates as well as to the __________ between
these plates.
directly
proportional
distance
type of capacitor that have different construction, inner and outer cylindrical structures.
Cylindrical Capacitors
The dielectric in the cylindrical capacitor is placed ______________
between these
two charged cylinders (inner and outer cylindrical structures)
The capacitance of a ____________ capacitor varies directly with its length.
Cylindrical capacitors
Increasing the amount of dielectric in the cylindrical capacitor ____________ the capacitance
increases
a _____ cylindrical capacitor offers higher capacitance than a _____. Such variation means that an increase in the_____ between the two charged cylinders will increase the amount of _______ to be done to move a charge from one cylinder to the other, therefore increasing the _____ across the
capacitor.
fat or large; thin one
distance; work
voltage
internal spherical structure is one of the charged bodies of the _______ capacitor. The other charged body is the outer spherical structure that covers the internal sphere. This is similar to that of a cylindrical capacitor
Spherical capacitor
The capacitance of this capacitor varies directly with its overall _____
radius
Increasing the _____ of Spherical capacitor will enlarge the spherical surface, consequently widening the _______ between the two charged spheres with that the amount of dielectric also surges, thus ______ the capacitance offered by the
capacitor.
radius; distance; boosting
boosting the capacitance of the spherical capacitor causes the work necessary to move a charge from one
sphere to another to also -______, thus intensifying the ______ across the
capacitor.
increase; voltage
DIFFERENT TYPES OF CAPACITORS
- Electrolytic Capacitor
- Mica Capacitor
- Paper Capacitor
- Film Capacitor
- Non-Polarized Capacitor
- Ceramic Capacitor
used when the large capacitor values are
required.
Electrolytic capacitor
The thin metal layer in an electrolytic capacitor is used for ________
and for the second electrode (cathode) a _______ which is in jelly or paste is used.
one electrode ; semi-liquid
electrolyte solution
The dielectric plate is a thin layer of _____
oxide (electrolytic capacitor)
Majority of electrolytic capacitors are ______
polarized.
The uses of this capacitor are generally in the DC power supply circuit
because they are in large capacitance and small in reducing ripple voltage.
Electrolytic capacitor
The applications of this electrolytic capacitors are coupling and decoupling
Electrolytic Capacitor
disadvantage of this is their relatively low voltage rating because of the
polarization of electrolytic capacitor.
Electrolytic capacitor
This capacitor is a group of natural minerals.
Mica
2 types of Mica Capacitor
clamped capacitors & silver mica capacitor.
Clamped mica capacitor is considered ________ because of their inferior characteristic
obsolete
_____ mica capacitor is prepared by sandwiching mica sheet coated with metal on both sides
and this assembly is then encased in epoxy to protect the
environment.
Silver
These capacitors are low loss capacitors, used at high frequencies and
is very stable chemically, electrically, and mechanically due to its specific crystalline structure binding and typical layered structure
Mica Capacitors
The construction of this capacitor is between the two tin foil sheets and they are separated from the paper or oiled paper and thin waxed.
Paper Capacitor
The capacitance range of this capacitor is from 0.001 to 2.000micro farad and the voltage is very high
which is up to 2000V.
Paper Capacitor
type of capacitor used a thin plastic as a dielectric. The film capacitor is prepared extremely thin using the sophisticated film drawing process.
Film capacitor
different types of film capacitors
- polyester film,
- metalized film,
- polypropylene film
- PTE film and
- polystyrene film
The main difference between these film capacitors is______ and is chose according to____
the material used as a dielectric and is chosen properly according to their properties
applications of the ____ capacitors are stability, low inductance, and low cost.
Film
The _______ is a heat resistance and is used in the aerospace and military technology.
PTE film capacitance
non-polarized capacitors are classified in to
two:
plastic foil capacitor and the electrolytic non-polarized capacitor
non-polarized capacitor requires the ______
Ac applications in a series or parallel with a signal or
power supply.
(Type of capacitor) The examples are the speaker crossover
filters and power factor correction network. In these two applications, a large AC voltage signal is applied across the capacitor
Non-Polarized Capacitor
This capacitor uses ceramic material as
dielectric.
Ceramic Capacitor
one of the first materials
used in the production of capacitors as an insulator.
ceramics
The two common types of ceramic capacitors are
________ and _____
multilayer ceramic capacitor (MLCC) and ceramic
disc capacitor.
The multilayer ceramic capacitors are prepared by using the ______ technology and they are smaller in size, therefore, it used widely. While the ceramic disc capacitor is manufactured by _______ on both sides and to achieve larger capacitance, these devices are made from multiple layers.
surface mounted (SMD)
coating a ceramic disc with silver contacts
effect or the ability of a capacitor to store charges
CAPACITANCE
capacitance is made up of two close conductors_______ and
separated by the _____ material.
conductors; dielectric
If the plates are connected to the power, then the plates accumulate the ______
Electric charge
(C) of a capacitor is mathematically defined as
the ratio of the
amount of charge (Q) in one plate to the potential difference (V) between
the plates.
one farad equals 1 ______
coulomb per volt.
capacitance of a parallel
plate capacitor is affected by the following factors:
a. Area of plates. The bigger the area of the plates, the greater is the
capacitance.
b. Distance between the
plates. The closer the
plates to one another, the
greater the capacitance.
c. Insulating material or
dielectric between them.
The dependence of the capacitance of a parallel plate capacitor on
the factors cited above is mathematically expressed as
C=epsilon(A/d)
Dielectrics serve three purposes:
- To keep the conducting plates from coming in contact, allowing for smaller plate separations and therefore higher capacitances;
- To increase the effective capacitance by reducing the electric field strength, which means you get the same charge at a lower voltage; and
- To reduce the possibility of shorting out by sparking (dielectric breakdown) during operation at high voltage
role of a dielectric inserted between the capacitor plates is to
_________
impede or block the charges passing through the material
Greater insulation of dielectric allows _____
more charges to be
stored.
Introducing a dielectric into a capacitor decreases the ________
which decreases the ____, which increases the ______
electric field,
voltage
capacitance.
A capacitor with a dielectric store the same charge as one without a______, but a _______. Therefore, a capacitor with a dielectric in it is more effective.
dielectric; lower voltage;
_______ is the work done in moving a unit positive charge from point A to point B in an electric field. Potential difference is designated as and is found by subtracting the potential at point A from the potential
at point B.
Potential Difference
If point A refers to the ground or infinity, the work done in bringing a unit
positive charge from ground or infinity to another point B is called the _________ at point B.
electric potential
unit of electric potential
volts (1 joule/coulomb J/C)
who devised the first electric cells
Alessandro Volta
On the other hand, if point A is not the ground nor the infinity, then the
work done in moving a unit positive test charge from point A to point B is
called the ___________
potential difference between points A and B.
________ an actual consideration of the potentials in the
circuit.
Potential difference is
existence of Potential Difference also identifies ________
the flow of charges
The amount of charge (Q) a capacitor can store depends on two
major factors- the _____ applied and the capacitor’s _______, such as its size.
voltage; physical
characteristics
electric field strength (E) is directly proportional to the
charge
Different capacitors will store different amounts of charge for the same
applied voltage, depending on their )_____
physical characteristics.
We define their
capacitance (C) to be such that the charge (Q) stored in capacitor is
___________
proportional to (C). (Q=CV)
There are three important rules for capacitors in
series:
1) The reciprocal of the total capacitance is equal to the sum of the reciprocals of the individual capacitance
2) The total potential difference or total voltage
is the sum of the potential differences across
each capacitor.
3) The total charge is equal to the individual
charge stored in each capacitor
parallel capacitors, the following rules
apply:
- The total capacitance is the sum of the individual capacitances.
- The voltage across all capacitors is equal to the voltage across each
capacitor. - The total charge is equal to the sum of the individual charges.
= 1 2 3
