Different Types of Capacitors

A capacitor is a passive electric element that accumulates energy in the form of electrostatic field. In simple words, capacitor includes 2 conducting plates alienated by the dielectric (an insulating material). The capacitance is inversely relative to the alienation amid the plates and it’s directly relative to the surface area of the conducting plates. Capacitance also relies on the dielectric constant of the material alienating the plates.The customary unit of capacitance is termed as farad, abbreviated. This is a huge unit; other universal units are known as microfarad, abbreviated 1 μF =10-6F (μF) & the picofarad, abbreviated 1 pF = 10-12F (pF).

“An electric circuit element used to store charge temporarily, consisting in general of two metallic plates separated and insulated from each other by a dielectric, also known as condenser.” A capacitor in general is like a battery. The common factor which is there in a battery & capacitor is  that  they  both  store  electric  energy.  Capacitors  store  electrons  inside  it  for  any  given  time  period.  A  capacitor  is  a  two – ended  gear  that  includes  2  conducting  units  divided  by  a  non-conducting  material.  A  capacitor  actually  comprise  of  2 conducting surfaces on which energy is stored these surfaces are divided by a lean insulating sheet which has an extremely huge resistance.Some  ordinary  non-conductive  materials  that  universally  exist  in  a  capacitor  are  Teflon,  ceramic,  porcelain  and  cellulose. The dielectric is a material that states the type of capacitor you are using and what is its specific usage. It depends on the kind of dielectric being utilized and the size for the application of high voltage or high frequency appliances.Capacitors are  manufactured  for  a  variety  of  products;  some  capacitors  are  so  small  that  they  are  made  for  products  like calculators, while other super capacitors are manufactured to be incorporated in computer bus. One can see capacitors in all sorts  of  HVAC  systems  which  includes  defrost  boards  &  circuit  boards.  The  most  ordinary  type  of  capacitor  employed  in HVAC system are start capacitor, dual run capacitor & run capacitor. Capacitors in Series:
When  capacitors  are  connected  in  series  the  total  capacitance  is  even  less  than  any  one  of  the  capacitors’  connected  in series, individual capacitance. If more than two capacitors are connected in series, the whole outcome is of a solitary (equa
l) capacitor  which  has  the  total  sum  of  the  plate  space  of  the  single  capacitor.  As  we  very  well  know  that  a  rise  in  the  plate spacing, with rest of the factors unaltered, outcomes in fall of capacitance. Therefore,  the  overall  capacitance  is  lower  than  any  solitary  of  the  individual  capacitor’s  capacitance.  For  calculating  the total capacitance of capacitors connected in series formula is given below:-  Capacitors in Parallel:
When capacitors are united in parallel the overall capacitance is the total of the solitary capacitor’s capacitance. If more than 2 capacitors are linked in parallel, the whole outcome is that of a solo correspondent capacitor which has the sum total of the
plate  surface  of  the  solo  capacitor.  As  we  have  experienced  that  an  increase  in  the  plate  surface,  while  other  essential factors remain same, the outcome is an increase in the capacitance.The  formula  to  evaluate  parallel resistance is same as for calculating total capacitance of capacitors connected in series.Types of Capacitors:
Capacitors can be employed in a number of different manners in a variety of electronic circuits. Even though their method of functioning  remains  precisely  similar  they  can  be  employed  to  supply  a  range  of  different  circuit  operations  such  as-
Coupling  capacitor,  Smoothing  capacitor,  Decoupling  capacitor.  There  are  many  other  types  of  capacitors  too  that  can  be employed, maximum of them are discussed below:
1. Ceramic Capacitor: Ceramic capacitor is found in many appliances ranging from radio to RF. By far ceramic capacitors are the most commonly used  capacitors;  this  is  because
these  capacitors  are  cheap,  reliable  &  their  loss  factor  is  much  lower.  These  ceramic capacitors are used in both leaded and surface mount formats.Ceramic  is  most  widely  employed  capacitor  which  is  employed  in  many  appliances  &  electronic  gears  now -a-days.  At present  ceramic  capacitors  are  available  in  a  wide  range  of  formats  such  as  leaded  constituents  to  surface  mount technology.  Leaded  version  of  disc  ceramic  capacitors  is  broadly  accessible.  These  ceramic  capacitors  are  employed practically in each & every sort of electric equipment. The exact performance of a ceramic capacitor basically relies in kind of dielectric employed.Ceramic capacitors are considered as workhorses of current capacitor world.Ceramic capacitors are obtainable currently in 3 major types even though additional styles are also available:

 2. Electrolytic Capacitor:
This type of capacitor is polarized. These capacitors are capable of offering higher capacitance value -generally above 1μF, this type of capacitor is commonly used in low frequency applications. Electrolytic capacitor has been employed in many appliances for a number of years. The plates of this capacitor are crafted from conducting aluminum foil. Owing to aluminum film the plates can be made extremely thin and these plates are flexible as well.  Hence these plates can be  packed at  the end of the construction procedure. The two plates included in this capacitor are a bit different. The 1st one is coated with an insulating oxide sheet and a paper spacer drenched in electrolyte is positioned amid  them. The foil insulated by the oxide coating is anode whereas the liquor electrolyte and the 2nd foil operate as cathode. Electrolytic capacitor properties:

3. Tantalum Capacitor:
These  capacitors  are  even  polarized  and  they  too  supply  extremely  high  capacitance  value  for  their  volume.  This  kind  of capacitor is extremely bigoted of being reversely biased, frequently causing explosion when applied under pressure. A  tantalum  capacitor  consists  of  a  porous  tantalum  core  fragment  bordered  by tantalum pentoxide. A tantalum cable is introduced into the core fragment and then expands axially from the constituent. The tantalum pentoxide coating is layered  with graphite, manganese dioxide, a silver conductive outer layer and at last solder. Since year 1960, tantalum capacitors have been improving owing to the advancement and development of superior charge tantalum powders, unswervingly contributing to the blueprint of small tantalum capacitors. A  tantalum  capacitor  consists  of  a  porous  tantalum  core  fragment  bordered  by There are a number of benefits of employing tantalum capacitor are as follows:

Tantalum  capacitors  can be  located  in  laptop,  PCs,  airbag  circuitry  in  trucks  &  cars,  mobile  phones,  pagers  and  a  broad range of other devices. 4. Variable Capacitor:
A variable capacitor is a kind of condenser which helps in accumulating energy by generating electric fields. The forte of this gadget is that the capability to preserve  power  can  be  altered
either repetitively or deliberately through mechanical or electronic methods. Variable capacitor’s capacitance may be altered all through the lifetime of the gadget itself . A mechanical structure is employed in the capacitor, which permit altering the remoteness amid the different sets of plates, or specifically, the surface of the overlying plate  area,  together  with  the  variable  capacitance  diodes.  All  these  alter  their  capaci
tance behavior owing to the reverse voltage bias application.Various types of variable capacitor are accessible. They are as follows:

5. Paper Capacitor:
Paper  capacitors  are  prepared  from  paper  or  oil-impregnated  paper  and  aluminum  foil  sheets  spin  into  a  drum  and conserved  with  wax.  These  paper  capacitors  were  normally  employed  but  are  now  substituted  by  the  polymer  or  plastic made capacitors. The paper capacitors are large, extremely hygroscopic and drenches dampness which roots to loss to the dielectric undignified its total performance is the main disadvantage with this sort of capacitors. The other options consist of paper-polyester, Kraft paper and oil-impregnated capacitor.Some other capacitor types are as follows: 6. Silver Mica Capacitor:
This type of capacitor is not in use much these days but this kind of capacitor still supply very superior level of constancy, lower loss & accuracy where space is not a matter of concern.
7. Polystyrene Film Capacitor:These are relatively cheap sort of capacitors but supply a close tolerance capacitor wherever required. These are tubular in shape; this is because the plate or dielectric sandwich is rolled collectively.
8. Polyester Film Capacitor:These capacitors are employed where cost is a concern as they do not supply a superior tolerance. These capacitors are in general only accessible as leaded electric constituents.
9. Polycarbonate Capacitor:This type of capacitoris applied in  appliances where performance & reliability is important. The polycarbonate film in extremely steady and allows superior tolerance capacitor to be manufactured which will uphold capacitors capacitance value over time.
10. Metalized Polyester Film Capacitor:
This is basically a polyester film capacitor the only difference amid the two is that in metalized polyester capacitor, polyester film is metalized. The metalized polyester film capacitors are usually only acces
sible as leaded electric constituents.
11. Polypropylene Capacitor:
This capacitor is employed when a superior tolerance is required than polyester capacitors supply. This capacitor makes use of polypropylene film for the dielectric. These capacitors are usually only accessible as leaded electric constituents.
12. Glass Capacitors:
This  capacitor  makes use of glass for the dielectric. This is an expensive capacitor but offer extremely superior level of performance in means of very low loss, higher RF curre
nt ability, no piezo-electric noise and some other salient attributes that make them perfect for several performance RF applications.
13. Super Capacitors:
Super  capacitors  come  from  a  family  of  electrochemical  capacitors.  These capacitors are sometimes named as electric double layer capacitor (EDLC) or ultracapacitor. They do not comprise of any traditional solid dielectric. The capacitance value of a super capacitor is determined on the basis of 2 storage principles; these 2 principles contribute to  capacitor’s overall capacitance.
Super capacitors are low in weight & cheap as well that’s why it’s the most popular capacitor in market these days. They are employed in most portable electronics & phones, together  with  aircrafts  &  automobiles.  The  new  technology super capacitors are flexible and biodegradable. Advantages of a Super Capacitor:

12. Ultra capacitor:
Ultracapacitors & super capacitors are one and the same, it has been explained above please refer.

Capacitor Capacitance Calculator:
This capacitance calculator evaluates the capacitance amid two parallel plates. The 1st calculator is metric, while the 2nd is inches. Small valued capacitors can be engraved into a PCB for RF purposes, but underneath ma
jority conditions it is extra cost effectual to make use of separate capacitors.A variety of dielectric constants are given below.

Equation:
C= K*EO*A/D, where Eo= 8.854×10-12

Where:
K-Is the dielectric constant of the material,
A-Is the overlying surface area of the plates,
d-Is the distance amid the plates, and
C-Is capacitance

Capacitor Bank:

A Capacitor Bank is a cluster of a number of capacitors of the similar rating that are coupled in series or parallel with one another  to  accumulate  electrical  energy.  The  resultant  bank  is  then  employed  to  work  against  or  correct  a  power  factor
pause or phase alteration in an AC (alternative current) power supply. They can also be employed in a DC (direct current) power supply to boost the ripple current capability of the power supply or to boost the total sum of energy accumulated.
Capacitor banks operate on the similar theory that a solitary capacitor do; they are intended to accumulate electrical energy, just at a bigger capability than a solitary appliance.

Applications of Capacitors:
Capacitors are used for a number of purposes, it’s the most commonly found device in any sort of electronic gadget. Each kind  of  capacitor  has  its  individual  advantage  &  disadvantage  and  as  a  result,  the  applications  of  the  ca
pacitor  can  be dissimilar.  A  number  of  capacitors  are  good  for  elevated  frequency  utilization,  while  others  can  be  employed  for  low frequency  purposes.  Without  a  doubt  it  is  essential  to  have  the  correct  capacitor  for  the  precise  usage  of  the  circuit  is  to
function appropriately.

 Source: http://www.electronicshub.org/different-types-of-capacitors/