1、AMSC N/A FSC 5910 INCH-POUND MIL-C-25F SUPERSEDING 5 October 2010 MIL-C-25E 12 January 2004 MILITARY SPECIFICATION CAPACITORS, FIXED, PAPER OR PLASTIC DIELECTRIC, DIRECT CURRENT, (HERMETICALLY SEALED IN METAL CASES), GENERAL SPECIFICATION FOR This specification is approved for use by all Departments
2、 and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This 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-curren
3、t (ac) component of the impressed voltage is small with respect to the dc voltage rating. 1.2 Classification. 1.2.1 Part or Identifying Number (PIN) 3.1. Capacitors specified herein (see ); are identified by a PIN that is in the following form, and as specified (see 3.1 and 6.1): 1.2.1.1 Style. The
4、style is identified by the two-letter symbol “CP” followed by a two-digit number; the letters identify direct-current, paper-dielectric, fixed capacitors hermetically sealed in metal cases; the first digit identifies general shape of the case, and the second digit identifies specific details other t
5、han case size. Each style designation includes a family of case sizes. 1.2.1.2 Terminal. The only terminal still available is a solder lug (nonremovable), identified by the letter “B“. 1.2.1.3 Circuittable I. The circuit diagram and the number of terminals associated with it are identified by a sing
6、le symbol as shown in . CP53 B 1 E B 105 K 1 Style (1.2.1.1) Terminal (1.2.1.2) Circuit (1.2.1.3) Characteristic (1.2.1.4) Voltage (1.2.1.5) Capacitance (1.2.1.6) Capacitance tolerance (1.2.1.7) Vibration grade (1.2.1.8) INACTIVE FOR NEW DESIGN after 21 June 1968 Comments, suggestions, or questions
7、on this document should be addressed to: DLA Land and Maritime, ATTN: VAT, Post Office Box 3990, Columbus, OH 43218-3990, or emailed to capacitorfilterdla.mil. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at ht
8、tps:/assist.daps.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-25F 2 TABLE I. Circuit diagram and number of terminals. Circuit diagram Number of terminals 2 1 3 3 2 1.2.1.4 Characteristic. The characteristic is identified by a single
9、 letter in accordance with table II. TABLE II. Characteristic. Characteristic Values of characteristics E and F K High ambient test temperature, degrees centigrade 3C Low ambient test temperature, degrees centigrade 3C Life-test dc voltage in percent of the voltage rating at +40C (see 4.6.15): Watt-
10、second group: I: 1A (0.08 watt-second and less) 1B (0.08 + to 0.5 watt-second) II (0.5 + to 5 watt-seconds) III (5 + to 50 watt-seconds) IV (greater than 50 watt-seconds) +85C -55C 140 140 130 110 90 +125C -55C 140 120 - - - - - - - - - 1.2.1.5 Voltage rating6.9. The dc voltage rating for continuous
11、 operation at +40C, except for characteristic K, which is +85C, is identified by a single letter in accordance with table III (see ). TABLE III. DC voltage rating. Symbol DC voltage rating (volts) B C E F G 100 200 400 600 1,000 1.2.1.6 Capacitance. The nominal capacitance value expressed in picofar
12、ads (pf) is identified by a three-digit number; the first two digits represent significant figures and the last digit specifies the number of zeros to follow. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-25F 3 1.2.1.7 Capacitance tolerance.
13、The capacitance tolerance in percent is identified by a single letter in accordance with table IV. TABLE IV. Capacitance tolerance. Symbol Capacitance tolerance (percent) K V 10 +20, -10 1.2.1.8 Vibration grade. The only vibration grade still available is grade 1 (10 to 55Hz). 1.2.2 Voltage rating v
14、ersus temperature3.1. Capacitors of characteristic K have a dc voltage rating for continuous operation at +85C, and capacitors of all other characteristics have a dc voltage rating for continuous operation at +40C as specified (see ). Voltage derating at other ambient temperatures may be necessary i
15、n order to realize equivalent life (see 3.1, 6.8, and 6.8.1). The permissible operating voltages, while based on incomplete data, are the capacitor suppliers best estimate to provide a life expectancy of 8,800 hours of continuous operation at high ambient temperatures. Longer life can be expected of
16、 all types by operation at still lower voltages; for example, a life expectancy of approximately 44,000 hours may be obtained by operation at 70 percent of the voltage specified. Also a life longer than 8,800 hours may be expected at the voltage specified if the high temperature prevails for only a
17、portion of the whole operating time. 1.2.2.1 AC component. The rating given is the steady-state dc voltage, or the sum of the dc voltage and the peak ac voltage, provided that the peak ac voltage does not exceed 20 percent of the rating at 60 Hertz (Hz), 15 percent at 120 Hz, or 1 percent at 10,000
18、Hz. Where heavy transient or pulse currents are encountered, the requirements of this specification are not sufficient to guarantee satisfactory performance and due allowance must be made, therefore, in the selection of a capacitor. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this s
19、ection are specified in sections 3 and 4 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are
20、 cautioned that they must meet all specified requirements documents cited in sections 3 and 4 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications. standards. and handbooks6.2. The following specifications, standards, and handbooks form a part of this
21、 document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract (See ). DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-C-25/4 - Capacitor, Fixed, Paper (or Plastic) Dielectric, Direct Current, (Hermetically Sealed in Metal
22、lic Cases), Styles CP53, CP54 and CP55. MIL-C-25/6 - Capacitor, Fixed, Paper-Dielectric, Direct Current, (Hermetically Sealed in Metallic Cases), Styles CP67 and CP69. DEPARTMENT OF DEFENSE STANDARDS MIL-STD-202 - Test Method Standard Electronic and Electrical Component Parts. (Copies of these docum
23、ents are available online at https:/assist.daps.dla.mil/quicksearch/ or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-25F 4 2.3 Non-G
24、overnment publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. AMERICAN SOCIETY FOR TESTING MATERIALS ASTM D92 - Standard Test Method for Flash and
25、 Fire Points by Cleveland Open Cup Tester. (Copies of this document may be ordered online at www.astm.org or from the American Society for Testing Materials, 1916 Race Street, Philadelphia, PA 19103.) 2.4 Order of precedence. Unless otherwise specified herein or in the contract, in the event of a co
26、nflict between the text of this document and the references cited herein (except for related specification sheets), the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS
27、 3.1 Specification sheet6.2. The individual item requirements shall be as specified herein and in accordance with the applicable specification sheet. In the event of any conflict between requirements of this specification and the specification sheet, the latter shall govern (see ). 3.2 Qualification
28、4.4. Capacitors furnished under this specification shall be products that are authorized by the qualifying activity for listing on the applicable qualified products list before contract award (see and 6.3). 3.3 Material. The material shall be as specified herein. However, when a definite material is
29、 not specified, a material shall be used which will enable the capacitors to meet the performance requirements of this specification. Acceptance or approval of any constituent material shall not be construed as a guaranty of the acceptance of the finished product. 3.3.1 Insulation, impregnating, and
30、 sealing compounds6.11. Compounds used in the impregnation and filling of capacitors shall be chemically inactive with respect to the capacitor unit and the case (see 3.4.1, , and 6.12). The compounds, either in the state of original application or as a result of having aged, shall have no adverse e
31、ffect on the performance of the capacitor. For liquid-filled capacitors, the same material shall be used for impregnating as is used for filling. 3.3.2 Metals3.11. Metals shall be of a corrosion resisting type, or shall be plated or treated to resist corrosion (see ). 3.4 Interface and physical dime
32、nsions3.1. Capacitors shall meet the interface and physical dimensions specified (see ). 3.4.1 Case. Each capacitor shall be enclosed in a hermetically-sealed metal case which will protect the capacitor element from moisture and mechanical damage under all of the specified test conditions. 3.4.2 Cap
33、acitor elements. The capacitor elements shall consist of conducting layers separated by two or more layers of dielectric tissues (paper). 3.4.2.1 Noninductive construction3.1. Capacitors having capacitance and dc voltage ratings equal to or less than 1 microfarad and 3,000 volts, respectively, shall
34、 have extended foil construction, tab construction, or an equivalent construction. When tab construction is used, each pair of tabs shall be brought out from opposite foils within one turn of the foil winding from each other, except as specified (see and 6.13). 3.4.3 Terminals. 3.4.3.1 Case as termi
35、nal. When the case is a terminal, any protective coating applied to the mounting surface shall be such as to provide a direct conducting path for an electric current from the case to the surface on which it is mounted. Provided by IHSNot for ResaleNo reproduction or networking permitted without lice
36、nse from IHS-,-,-MIL-C-25F 5 3.4.3.2 Solder lugs and solder-lug terminals6.16. Solder lugs and solder lug-terminals may be of any shape, providing dimensional limits are met, and shall be coated with solder having a tin content of 40 to 70 percent (see ). 3.4.4 Pure tin6.7. The use of pure tin, as a
37、n underplate or final finish, is prohibited both internally and externally. Tin content of capacitor components and solder shall not exceed 97 percent, by mass. Tin shall be alloyed with a minimum of 3 percent lead, by mass (see ). 3.5 Dielectric withstanding voltage 4.6.2. When tested as specified
38、in , capacitors shall withstand the direct current (dc) potential specified without permanent damage or open-circuiting or short-circuiting. 3.6 Insulation resistance. 3.6.1 Terminal to terminal 4.6.3. When capacitors are tested as specified in , the insulation resistance shall not be less than the
39、applicable values specified in table V (see figure 1). 3.6.2 Terminals to case 4.6.3. When capacitors are tested as specified in , the insulation resistance, measured between any terminal and the case, when the case is not a terminal, shall exceed 3,000 megohms. TABLE V. Terminal-to-terminal insulat
40、ion resistance measurements. Capacitance rating Minimum insulation resistance 0.33 microfarads, and less Characteristic E Greater than 0.33 microfarads 0.033 microfarads and less Greater than 0.033 microfarads At +25C 3C6,000 megohms 1/ 2,000 megohm-microfarads 2/ 600 megohms At +85C 3C 20 megohm-mi
41、crofarads 2/ 0.33 microfarads and less Characteristic F Greater than 0.33 microfarads 0.033 microfarads and less Greater than 0.033 microfarads At +25C 3C4,500 megohms 1/ 1,500 megohm-microfarads 2/ 450 megohms At +85C 15 megohm-microfarads 2/ 0.33 microfarads and less Characteristic K Greater than
42、0.33 microfarads 0.067 microfarads, and less Greater than 0.067 microfarads At +25C 3C18,000 megohms 1/ 6,000 megohm-microfarads 2/ 150 megohms At +125C 3C 10 megohm-microfarads 2/ 1/ For corrections, if measurements are made at other temperatures between +20C and +35C, see table VI. 2/ Product obta
43、ined by multiplying the capacitance in microfarads by the insulating resistance in megohms. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-25F 6 TABLE VI. Insulation-resistance correction factors. Degrees centigrade Correction factor Degrees c
44、entigrade Correction factor +20 +21 +22 +23 +24 +25 +26 +27 1.42 1.33 1.24 1.16 1.08 1.00 0.94 0.87 +28 +29 +30 +31 +32 +33 +34 +35 0.82 0.76 0.71 0.67 0.63 0.59 0.55 0.51 FIGURE 1. Graphical representation of insulation resistance requirements specified in 3.6.1 and table V. Provided by IHSNot for
45、ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-25F 7 3.7 Capacitance 4.6.4. When measured as specified in , the capacitance shall be within the tolerance shown in the type designation (see 3.1). 3.8 Dissipation factor 4.6.5. When measured as specified in , the dissi
46、pation factor shall be not more than 1.0 percent. 3.9 Barometric pressure (reduced) (Qualification inspection only)4.6.6. Capacitors shall withstand the dc potential specified in without visible damage, external flashover, open-circuiting or short-circuiting (see 3.1). 3.10 Vibration (low frequency)
47、 4.6.7. When capacitors are tested as specified in , 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) 4.6.8. As a result of the test specified in , there shall be no harmful
48、 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
49、. In addition, there shall be not more than 10 percent corrosion of the terminal hardware or mounting surface. 3.12 Thermal shock and immersion 4.6.9. When tested as specified in , 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
