Types Of Capacitors And Their Applications

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Types Of Capacitors And Their Applications
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Types Of Capacitors And Their Applications
Introduction

• Capacitor is one of mostly used component in
  electronic circuit design. It plays an important
  role in many of the embedded applications. It is
  available at different ratings. It consists of
  two metal plates separated by a non conducting
  substance, or dielectric. A capacitor stores an
  electrical charge between the two plates, The
  unit of capacitance is Farads (F). It is often
  storage depots for analog signals and digital data

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Types Of Capacitors And Their Applications
Common Types of Capacitors
1. Film Capacitors 2. Ceramic Capacitors 3.
Electrolytic Capacitors 4. Variable Capacitors
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Types Of Capacitors And Their Applications
Film Capacitors

• Film Capacitors comprising of a generally
  expansive group of capacitors with the
  distinction being in their dielectric properties.
  
• Film Capacitors are available in almost any value
  and voltages as high as 1500 volts.
• They come in any tolerance from 10 to 0.01.
• There are two types of film capacitors.
• They are radial lead type and axial lead type.

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Types Of Capacitors And Their Applications
Film Capacitors

• The electrodes of film capacitors may be
  metalized aluminium or zinc.
• It applied on one or both sides of the plastic
  film.

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Types Of Capacitors And Their Applications
Film Capacitors

• It resulting in metalized film capacitors called
  film capacitors.
• Film capacitors additionally arrive in a
  combination of shapes and case styles.
• Film Capacitors are sometimes called plastic
  capacitors.
• It use polystyrene, polycarbonate or Teflon as
  their dielectrics.
• These film sorts need a much thicker dielectric
  film to lessen the danger of tears.

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Types Of Capacitors And Their Applications
Film Capacitors

• It is more suited to lower capacitance values and
  bigger case sizes.
• The film capacitors are physically larger and
  more expensive, they are not polarized.
• It can be used in AC voltage applications, and
  they have much more stable electrical parameters.
• Dependence of capacitance and dissipation factor.
• Film Capacitors can be applied in frequency
  stable Class 1 applications, replacing Class 1
  ceramic capacitors.

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Types Of Capacitors And Their Applications
Ceramic Capacitors

• Ceramic capacitors are used in high frequency
  circuits such as audio to RF
• Ceramic Capacitors are the best choice for high
  frequency compensation in audio circuits.
• These capacitors are also called as disc
  capacitors.
• Ceramic capacitors are made by coating two sides
  of a small porcelain or ceramic disc with silver
  and are then stacked together to make a
  capacitor.

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Types Of Capacitors And Their Applications
Ceramic Capacitors

• One can make both low capacitance and high
  capacitance in ceramic capacitors.

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Types Of Capacitors And Their Applications
Ceramic Capacitors

• It can be made by changing the thickness of the
  ceramic disc used.
• They come in values from a few Pico farads to 1
  microfarad.
• The voltage range is from a few volts up to many
  thousands of volts.
• Ceramics are inexpensive to manufacture and they
  come with several dielectric types.

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Types Of Capacitors And Their Applications
Electrolytic Capacitors

• It is most prevalently used capacitors which have
  a wide tolerance capacity.
• Electrolytic capacitors are available with
  working voltages up to about 500V.
• There are two types of electrolytic capacitor,
  tantalum and aluminium in common.
• Tantalums capacitors have ordinarily better
  exhibition, higher value.

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Types Of Capacitors And Their Applications
Electrolytic Capacitors

• The dielectric properties of tantalum oxide is
  much superior to those of aluminium oxide.

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Types Of Capacitors And Their Applications
Electrolytic Capacitors

• It has an easier leakage current and better
  capacitance strength which makes them suitable
  for obstructing, decoupling, filtering
  applications.
• The thickness of the aluminium oxide film and
  heightened breakdown voltage gives the capacitors
  exceptionally elevated capacitance values for
  their size.
• In a capacitor the foil plates are anodized by a
  dc current thus setting of the extremity of plat
  material and confirming polarity of its side.

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Types Of Capacitors And Their Applications
Variable Capacitors
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Types Of Capacitors And Their Applications
Variable Capacitors

• A Variable Capacitor is one whose capacitance may
  be intentionally and repeatedly changed
  mechanically.
• This type of capacitors utilized to set frequency
  of resonance in LC circuits.
• To adjust the radio for impedance matching in
  antenna tuner devices.

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Types Of Capacitors And Their Applications
How to Know the Value of Capacitors?

• Capacitors are the essential components of an
  electronic circuit without which the circuit
  cannot be completed.
• Different types of capacitors like Electrolytic
  capacitor, Disc capacitor, Tantalum capacitor etc
  are used in circuits.
• Electrolytic capacitors have value printed on its
  body so that its pins can be easily identified.
• Usually the large pin is positive.

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Types Of Capacitors And Their Applications
How to Know the Value of Capacitors?

• The black band present near the negative terminal
  indicates the polarity.
• But in Disc capacitors, only a number is printed
  on its body.
• It is very difficult to determine its value in
  PF, KPF, uF, n etc.
• For some capacitors the value is printed in terms
  of uF, while in others a EIA code is used.

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Types Of Capacitors And Their Applications
Methods to Identify the Capacitor and to
Calculate its Value
1.The number on the capacitor represents the
capacitance value in Pico Farads. For example, 8
8PF 2. If the third number is zero, then the
value is in P e.g. 100 100PF 3. For a 3 digit
number, the third number represents the number of
zeros after the second digit For example, 104
10 0000 PF 4. If the value is obtained in PF,
it is easy to convert it into KPF or uF, PF /
1000 KPF or n, PF / 10, 00000 uF. For a
capacitance value of 104 or 100000 in pF, it is
100KpF or n or 0.1uF.
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Types Of Capacitors And Their Applications
Conversion Formula

• n x 1000 PF PF/1000 n PF/1,000,000 uF uF x
  1,000,000 PF uF x 1,000,000/1000 n
  n1/1,000,000,000F uF 1/ 1000,000 F.
• The letter below the capacitance value determines
  the tolerance value.
• 473 473 K
• For a 4 digit number, if the 4th digit is a zero,
  then the capacitance value is in pF.
• E.g. 1500 1500PF

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Types Of Capacitors And Their Applications
Conversion Formula

• If the number is just a floating point decimal
  number, the capacitance value is in uF.
• E.g. 0.1 0.1 uF
• If an alphabet is given below the digits, it
  represents a decimal and the value is in KPF or n
• E.g. 2K2 2.2 KPF
• If the values are given with slashes, the first
  digit represents value in UF, second its
  tolerance and third its maximum voltage rating
• E.g. 0.1/5/800 0.01 uF / 5 / 800 Volt.

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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are
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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are

• Without a Capacitor, the circuit design will not
  be complete since it has an active role in the
  functioning of a circuit
• The Capacitor has two electrode plates inside
  separated by a dielectric material such as paper,
  mica.
• What happens when the electrodes of the capacitor
  are connected to a power supply?
• The capacitor charges to its full voltage and
  retains the charge.

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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are

• The capacitor has the ability to store current
  which is measured in terms of Farads.
• The capacitance of a capacitor depends on the
  area of its electrode plates and the distance
  between them.
• Disc capacitors do not have polarity.
• So that they can be connected either way round.

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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are

• Disc capacitors are mainly used for coupling /
  decoupling the signals.
• The Electrolytic capacitors on the other hand
  have polarity.

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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are

• If the polarity of the capacitor changes, it will
  explode.
• Electrolytic capacitors are mainly used as
  filters, buffers.
• Each capacitor has its own capacitance which is
  expressed as the Charge in the capacitor divided
  by the Voltage.
• When you use a capacitor in a circuit, some
  important parameters should be considered.

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Types Of Capacitors And Their Applications
Some Common Disc Capacitors Are

• First is its Value. Select a proper value.
• Either low or high value depending on the circuit
  design.
• The value is printed on the body of most of the
  capacitors in uF or as EIA code.
• In Color coded capacitors, the values are
  represented as color bands.
• By using a capacitor color code chart it is easy
  to identify the capacitor.

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Types Of Capacitors And Their Applications
Color Chart to Identify a Color Coded Capacitor

• Resistors each band on the capacitor has a value.

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Types Of Capacitors And Their Applications
Color Chart to Identify a Color Coded Capacitor

• The value of the First band is the First number
  in the color chart.
• The value of the Second band is the Second number
  in the color chart.
• The Third band is the multiplier as in the case
  of a resistor.
• Fourth band is the Tolerance of the capacitor.
• The Fifth band is the body of the capacitor which
  represents the Working voltage of the capacitor.
• The Red color represents 250 volts and Yellow
  represents 400 volts.

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Types Of Capacitors And Their Applications
Capacitor Tolerance and Working voltage

• Tolerance and Working voltage are two important
  factors to be considered.
• No capacitor has the rated capacitance and it may
  vary.
• So use a good quality capacitor like Tantalum
  capacitor in sensitive circuits like oscillator
  circuits.
• The working voltage of the electrolytic capacitor
  is printed on its body.

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Types Of Capacitors And Their Applications
Capacitor Tolerance and Working voltage

• Leakage current is another problem in capacitors.
• Some of the charge will leak, even if the
  capacitor is charging
• This is verse in Timer circuits since the timing
  cycle depends on the charge/discharge time of the
  capacitor.
• Low leakage Tantalum capacitors are available and
  use them in Timer circuits.

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Types Of Capacitors And Their Applications
Understanding the Reset Capacitor Function in
Microcontroller

• A Reset is used to start-up or to restart the
  AT80C51 microcontroller functionality.
• A reset pin follows two conditions to start up
  the microcontroller. They are
• 1) Power supply must be in the specified range.
• 2) The reset pulse width duration must be at
  least two machine cycles.

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Types Of Capacitors And Their Applications
Understanding the Reset Capacitor Function in
Microcontroller

• The reset must be kept active until all two of
  the conditions are respected.
• In this type of circuit, the capacitor and
  resistor arrangement from the supply is connected
  to reset pin no. 9.
• While the supply switch is ON, the capacitor
  starts charging.
• At this time, capacitor acts like a short circuit
  in the beginning.

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Types Of Capacitors And Their Applications
Understanding the Reset Capacitor Function in
Microcontroller

• When reset pin set to HIGH, the microcontroller
  goes to the power on state and after some time
  the charging stops.
• When charging stops, the reset pin goes to ground
  because of the resistor.
• The reset pin should go to high then go to low,
  then program starts from begging.

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Types Of Capacitors And Their Applications
Advantages

• Long life, with little degradation over hundreds
  of thousands of cycles.
• Low cost per cycle
• Good reversibility
• Very high rates of charge and discharge.
• Extremely low internal resistance (ESR) and
  consequent high cycle efficiency (95 or more)
  and extremely low heating levels.
• High output power.

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Types Of Capacitors And Their Applications
Disadvantages

• The amount of energy stored per unit weight is
  considerably lower than that of an
  electrochemical battery.
• As with any capacitor, the voltage varies with
  the energy stored.
• Has the highest dielectric absorption of any type
  of capacitor.
• Cells have low voltages serial connections are
  needed to obtain higher voltages.
• Voltage balancing is required if more than three
  capacitors are connected in series.
• Linear discharge voltage prevents use of the full
  energy spectrum.

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Types Of Capacitors And Their Applications
Applications

• Capacitors have applications in both electrical
  and electronics.
• They are used in filter applications, energy
  storage systems, motor starters and signal
  processing devices.
• Capacitors are used for power factor correction.
• Use of capacitors includes smoothing the ripples
  from AC in power supply, coupling and decoupling
  the signals, as buffers etc.

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Types Of Capacitors And Their Applications
Conclusion

• The comparisons between the different types of
  capacitors are generally made with regards to the
  dielectric used between the plates. Some
  capacitors look like tubes, small capacitors are
  often constructed from ceramic materials and then
  dipped into an epoxy resin to seal them.

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