MIL-C-25 Capacitors, Fixed, Paper Or Plastic Dielectric, Direct Current, \(Hermetically Sealed In Metal Cases\), General Specification ForThis specification covers the general requirements for direct-current \(dc\) paper-dielectric, fixed capacitors hermetically sealed in metal cases, intended primarily for filter, by-pass, and blocking purposes where the alternating-current \(ac\) component of the impressed voltage is small with respect to the dc voltage rating.

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MIL-C-25F

3.7 Capacitance. When measured as specified in 4.6.4, the capacitance shall be within the tolerance shown in the

type designation (see 3.1).

3.8 Dissipation factor. When measured as specified in 4.6.5, the dissipation factor shall be not more than 1.0

percent.

3.9 Barometric pressure (reduced) (Qualification inspection only). Capacitors shall withstand the dc potential

specified in 4.6.6 without visible damage, external flashover, open-circuiting or short-circuiting (see 3.1).

3.10 Vibration (low frequency). When capacitors are tested as specified in 4.6.7, there shall be no mechanical

damage, and the measurement shall show no evidence of intermittent contacts, open-circuiting or short-circuiting.

3.11 Salt atmosphere (corrosion). As a result of the test specified in 4.6.8, there shall be no harmful or extensive

corrosion, and at least 90 percent of any exposed metal surface of the capacitor shall be protected by the finish. For

capacitors with painted cases, not more than 10 percent of the surfaces shall be affected by flaking, peeling, or

blistering of paint. The marking shall remain legible. In addition, there shall be not more than 10 percent corrosion of

the terminal hardware or mounting surface.

3.12 Thermal shock and immersion. When tested as specified in 4.6.9, capacitors shall meet the following

requirements:

a. Dielectric withstanding voltage:

(1) Terminal to terminal: As specified in 3.5.

(2) Terminal to case (when case is not a terminal): As specified in 3.5.

b. Insulation resistance:

(1) Terminal to terminal: Not less than 30 percent of the value specified in 3.6.1.

(2) Terminal to case (when case is not a terminal): Not less than 50 percent of the value specified in 3.6.2.

In addition, there shall be no harmful or extensive corrosion of the capacitors. The marking shall remain legible.

3.13 Terminal strength. When capacitors are tested as specified in 4.6.11, there shall be no mechanical damage

to the capacitor or terminals; no part of any terminal shall loosen or rupture.

3.14 Moisture resistance. When tested as specified in 4.6.12, capacitors shall meet the following requirements.