| FILM CAPACITOR GUIDE |
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Application / Function Desired |
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Expected Capacitor Parameter |
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Circuit Diagram |
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| BLOCKING |
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| Once the capacitor is charged it passes no more DC (except for minor leakage, i.e., IR) hence C provides a high series impedance for limiting low frequency AC or DC current. |
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High insulation resistance. |
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DEKI RANGE
For C < 0.001 mf — Plain Polypropylene Film Capacitors.
For 0.001 < C £ 0.1 mf — Plain Polyester Film Capacitors.
For C > 0.1 mf — Metallised Polyester Film Capacitors. |
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| COUPLING & BYPASSING |
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| The capacitor actually acts as a conductor to AC (because of moving particles present in the dielectric) i.e., C provides a low series impedance for transferring AC signal information from one system to another. |
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Low dissipation factor
(tan d).
Low inductance. |
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DEKI RANGE
For C < 0.001 mf — Plain Polypropylene Film Capacitors.
For 0.001 < C £ 0.1 mf — Plain Polyester Film Capacitors.
For C > 0.1 mf — Metallised Polyester Film Capacitors. |
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| TIMING CIRCUITS |
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| In timing circuits capacitors are used to introduce time delays. |
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Stability of electrical characteristics (with reference to ambient temperature, etc.).
Close capacitance tolerance. |
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DEKI RANGE
For C £ 0.047 mf — Plain Polypropylene Film Capacitors.
For C > 0.047 mf — Metallised Polypropylene Film Capacitors.
PEP Film Foil Inductive for high temperature upto 110°C with high voltage and high frequency say 40kHz and 110 VRMS. |
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| TUNING AND OSCILLATION |
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| In tuning circuits capacitors and inductors are used to select the desired frequency signal. |
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Stability of electrical characteristics (with reference
to ambient temperature and frequency).
Close capacitance tolerance. |
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DEKI RANGE
For C £ 0.047 mf — Plain Polypropylene Film Capacitors.
For C > 0.047 mf — Metallised Polypropylene Film Capacitors.
PEP Film Foil Inductive for high temperature upto 110°C with high voltage and high frequency say 40kHz and 110 VRMS. |
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| SAMPLE AND HOLD CIRCUIT |
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| In this application C retains the stored energy. |
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Low dielectric absorption. |
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DEKI RANGE
For C £ 0.047 mf — Plain Polypropylene Film Capacitors.
For C > 0.047 mf — Metallised Polypropylene Film Capacitors.
PEP Film Foil Inductive for high temperature upto 110°C with high voltage and high frequency say 40kHz and 110 VRMS. |
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