Construction of Mica Capacitor And its Application

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Construction of Mica Capacitor And Its Application
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Construction of Mica Capacitor And its Application
Introduction

• A capacitor is called as a condenser and earlier
  to that named as a Permittor. It is a two
  terminal passive electrical component, used to
  store electrical energy in an electric field.
  There are different kinds of capacitors are
  available in the market and such one is Mica
  Capacitors.

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Construction of Mica Capacitor And its Application
What is a Mica Capacitor?

• The term Mica is a collection of natural
  minerals.
• Silver mica capacitor is a capacitor that uses
  the name mica as the dielectric.
• These capacitors are classified into two types

• Silver mica capacitor
• Damped mica capacitor.

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Construction of Mica Capacitor And its Application
What is a Mica Capacitor?

• Silver mica capacitors are used in its place of
  clamped mica due to their lower characteristics.
• Mica capacitors are low loss capacitors which are
  used where the high frequency is required and
  their value doesnt change much over time.

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Construction of Mica Capacitor And its Application
What is a Mica Capacitor?

• These capacitors are constant chemically,
  mechanically and electrically due to its
  particular crystalline structure (typical layered
  structure).
• This creates it achievable to produce thin sheets
  in the order of 0.025-0.125 mm.
• The most frequently used micas are Phlogopite
  mica and Muscovite mica.
• The high difference in raw material work leads to
  high cost required for check sorting.
• Mica doesnt respond with most acids, oil, water
  and solvents.

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Construction of Mica Capacitor And its Application
Construction of Mica Capacitor

• The construction of Mica Capacitor is so simple.

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Construction of Mica Capacitor And its Application
Construction of Mica Capacitor

• Silver Mica Capacitors are made by covering the
  silver directly on the outside of mica.
• Covering this is to obtain the desired
  capacitance.
• After the layers are collected, electrodes are
  added the assembly is encapsulated. 
• Silver mica capacitors have a comparatively tiny
  capacitance value (between a few pF, upto a few
  nF). 

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Construction of Mica Capacitor And its Application
Construction of Mica Capacitor

• The largest capacitance capacitors can attain
  values of 1µF.
• Silver mica capacitors are typically rated for
  voltages between 100 1000 volts.
• There are particular high-voltage mica capacitors
  designed for RF TX employ which are rated at up
  to 10 kV.

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Construction of Mica Capacitor And its Application
How to Choose the Right Mica Capacitor

• When you are selecting the right mica capacitors
  you can filter the various attribute results so
  that you will be able to find the right silver
  mica capacitors.

• The following factors should check before
  choosing this capacitor

• Lead Spacing -3.6 mm, 5.9 mm, 8.7 mm, 11.1 mm
• Capacitance -2 pF, 22 pF, 47 pF, 100 pF, 470 pF
• Rated Voltage-from 50 V to 1 kV

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Construction of Mica Capacitor And its Application
Characteristics of Mica Capacitor

• The characteristics of the mica capacitor include
  the following

• Accuracy and Tolerance
• Stability
• Low losses

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Construction of Mica Capacitor And its Application
Characteristics of Mica Capacitor
Accuracy and Tolerance

• The values of smallest tolerance of a silver mica
  capacitor can be as low as 1.
• This is much superior than almost all other
  kinds of capacitors.
• In contrast, positive ceramic capacitors can
  include tolerances of up to 20.

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Construction of Mica Capacitor And its Application
Characteristics of Mica Capacitor
Stability

• These capacitors are very constant and very
  precise.
• Their capacitance changes small over time.
• This is due to the truth that there are no air
  spaces in the design which might change over
  time.
• Also, the assembly is guarded from other results
  by an epoxy resin.

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Construction of Mica Capacitor And its Application
Characteristics of Mica Capacitor
Stability

• This means that external effects like air
  humidity do not involve mica capacitors.
• Not only is their capacitance constant over time.
• Its also steady over an ample temperature,
  voltage frequency range.
• The standard temperature coefficient is around 50
  ppm/C.

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Construction of Mica Capacitor And its Application
Characteristics of Mica Capacitor
Low losses

• These have low inductive and resistive losses.
• The characteristics of these capacitors are
  generally frequency independent.
• Which permits for their use of high frequency.
• These better characteristics come at a price
  silver mica capacitors are large and costly.

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Construction of Mica Capacitor And its Application
Silver Mica Capacitor Properties

• Silver mica capacitors are used frequently due to
  its features like high level performance,
  superior in numerous areas than any other kind of
  capacitor.
• The particular properties of the mica capacitor
  are summarized below.

• High accuracy
• Temperature co-efficient
• Value range
• Low capacitance variation with voltage
• High Q

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Construction of Mica Capacitor And its Application
Advantages and Disadvantages of Mica Capacitor

• The advantages and disadvantages of mica
  capacitors mainly include

• Stable capacitance.
• Operates at high temperatures.
• Withstand at very high voltages.
• Low losses.
• Highly accurate and Dielectric provides good
  insulation.
• High cost and Proper sealing is required.

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Construction of Mica Capacitor And its Application
Applications for Mica Capacitors

• The applications of mica capacitors can be found
  in a large range of applications including the
  following

• Ripple filter and Decoupling for general
  electronic devices
• Resonant circuits
• Coupling circuits
• Time constant circuits
• High-power RF broadcast transmitters

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Construction of Mica Capacitor And its Application
Applications for Mica Capacitors

• The applications of mica capacitors can be found
  in a large range of applications including the
  following

• Defense Electronic Devices
• Power transfer circuits for low-capacitance
  snubber applications
• Radio or TV transmitters
• Cable TV amplifiers
• High voltage inverter circuits

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Construction of Mica Capacitor And its Application
Conclusion

• From the above information finally we can
  conclude that, these capacitors employ mica as
  the dielectric. They have high frequency
  properties due to very stable over time,
  inductive losses and low resistance. Mica
  capacitors are classified based on the different
  properties like working voltage, required
  capacitance and current handling capacity.

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