| TANGENT OF LOSS ANGLE (TAN d) |
The dissipation factor or tangent of loss angle is the power loss of the capacitor divided by the reactive power of the capacitor at a sinusoidal voltage of specified frequency.
Equivalent circuit of capacitor
tan d = vCR = 2 x p x f x C x R where R is the Equivalent Series Resistance.
The tangent at loss angle shall be measured under the same conditions as those given for the measurement of capacitance at one or more frequencies as prescribed in the detailed specifications.
The measuring method shall be such that the error does not exceed 10% of the specified value or 0.0001, whichever is higher. |
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| QUALITY FACTOR |
The reciprocal of tangent of loss angle
Q = 1 / vCR |
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| EQUIVALENT SERIES RESISTANCE (ESR) |
The ESR is the resistive part of the equivalent series circuit and is temperature and frequency dependent. The ESR can be calculated from the dissipation factor (tan d) as follows:
ESR = tan d / vC |
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| POWER DISSIPATION |
The power dissipated by a capacitor is a function of the voltage across or the current (I) through the equivalent series resistance ESR.
P = v x C x tan d x U2
P = 2 x p x f x C x tan d x U2
where f = frequency, tan d = maximum value specified,
U = rated voltage |
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| PULSE LOAD or RISE TIME (dv/dt) |
The maximum voltage pulse slope that the capacitor can withstand with a pulse voltage equal to the rated voltage. For pulse voltage other than the rated voltage the maximum voltage pulse slope may be multiplied by URDC and divided by the applied voltage.
dv/dt(max) = (dv/dt) x (VR / VPP) |
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| LEAD WIRE SPECIFICATION |
| Tin plated wire. |
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| ROBUSTNESS OF TERMINATION |
| a. Tensile: The force applied shall be |
Diameter of the wire |
Force |
(mm) |
(N) |
0.5 < d £ 0.8 |
10 |
0.8 < d £ 1.25 |
20 |
|
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| b. Bending: Two consecutive bends shall be applied in each direction. This test shall not apply if, in the detailed specifications the terminations are described as rigid. |
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| SOLDERING CONDITIONS |
Temperature: 235°±5°C
Immersion Speed: 25 mm / minute
Immersion Time: 2 sec ± 0.5 sec
Requirement: Minimum 95% area of lead wire should be fully covered with smooth and bright solder
Test conditions: As per IS 9000. |
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| TEMPERATURE DERATED VOLTAGE |
| For temperature between +85°C and 100°C a decreasing factor of 1.25% per °C on the rated voltage VR has to be applied. |
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| FILM/FOIL (INDUCTIVE) vs. METALLISED |
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Film/Foil Inductive |
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Metallised Non-inductive |
| • |
High dv/dt |
• |
Smaller in size as compared to film / foil capacitor |
| • |
High IR |
| • |
Good current carrying capability |
• |
High reliability (because of self healing property) |
| • |
Better capacitance stability |
• |
Connections of elements are made by means of metalspraying process and by welding the leads on to the end spray |
| • |
Lead connections are made of spot welding on the foil |
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| DIELECTRIC COMPARISON |
Parameters |
Polyester |
Polypropylene |
| |
(PET) |
(PP) |
Dielectric constant
23° C, 1 kHz |
3.25 |
2.2 |
Dissipation Factor
23° C, 1 kHz |
0.005 |
0.0002 |
Volume Resistivity
23° C |
1018 W cm |
1018 W cm |
Surface Resistivity
23° C, 80% RH |
1010 W |
1014 W |
| V / micron |
435V DC |
500V DC |
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