MIL-PRF-19978 Capacitors, Fixed, Plastic \(Or Paper-Plastic\) Dielectric \(Hermetically Sealed In Metal, Ceramic Or Glass Cases\), Established And Non-Established Reliability General Specification ForThis specification covers the general requirements for established reliability \(ER\) and non-established reliability \(non-ER\), direct current \(dc\), plastic or paper-plastic dielectric, fixed capacitors, hermetically sealed in metal or ceramic or glass cases. Capacitors meeting the established reliability requirements specified herein have failure rate \(FR\) levels ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.9\). These FRLs are established at a 90-percent confidence level and maintained at a 10-percent producer\'s risk and are based on life tests performed at maximum rated voltage and maximum rated temperature. An acceleration factor of 5:1 has been used to relate the life test data obtained at 140 percent of rated dc voltage at the applicable high test temperature to the rated voltage at the applicable high test temperature. This specification also covers removable mounting retainers for use with applicable capacitors \(see 3.1\). A parts per million \(ppm\) quality system is used for documenting and reporting the average outgoing quality of ER capacitors supplied to this specification. Statistical process control \(SPC\) techniques are required in the manufacturing process to minimize variation in production of ER capacitors supplied to the requirements of this specification.

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MIL-PRF-19978K

c. Examination after immersion: Capacitors shall be inspected for evidence of extensive corrosion and

unwrapping of, or mechanical damage to the insulating sleeves, when applicable.

4.7.14 Solderability (wire leads only, see 3.1) (see 3.18). Capacitors shall be tested in accordance with method

208 of MIL-STD-202. The following details shall apply:

a. Number of terminations to be tested: Both leads of the capacitor shall be subjected to the solderability test.

b. Depth of immersion in flux and solder: The leads shall be immersed to within .125 inch (3.18 mm) of the

capacitor body.

4.7.15 Shock (specified pulse) (see 3.19). Capacitors and retainers shall be tested in accordance with method

213 of MIL-STD-202. The following details shall apply:

a. Mounting: The body of the capacitor shall be securely fastened by mounting retainers. The leads shall be

soldered to rigidly supported terminals so spaced that the length of each lead from the capacitor shall be .5

inch .125 inch (12.7 mm  3.18 mm) from the edge of the supporting terminal.

b. Test condition letter: I (100 g's).

c. Electrical loading during shock: During the test, a potential of 125 percent of the dc voltage rating shall be

applied between the terminals of the capacitor.

d. Measurements during shock: During the test, observations shall be made to determine intermittent contact

or arcing or open-circuiting or short-circuiting. Detecting equipment shall be sufficiently sensitive to detect

any interruption with a duration of 0.5 ms or greater.

e. Examinations after test: Capacitors shall be visually examined for evidence of breakdown, arcing, fractures,

or any other visible mechanical damage. Retainers shall be visually examined for mechanical damage.

4.7.16 Terminal strength (see 3.20). Capacitors shall be tested in accordance with method 211 of MIL-STD-202.

The following details and exceptions shall apply:

a. Test condition letter: As specified (see 3.1).

b. Examination after test: The capacitors and terminals shall be examined for mechanical damage.

4.7.17 Dielectric absorption (see 3.21), (when specified, see 3.1). The capacitor shall be charged at the dc

voltage rating for 1 hour 1 minute. The initial surge current shall not exceed 50 milliamperes. At the end of this

period, the capacitor shall be disconnected from the power source and discharged through a 5 ohm 5 percent

resistor for 10 seconds 1 second. The discharge resistor shall be disconnected from the capacitor at the end of the

10 second discharge period, and the voltage remaining on the capacitor (recovery voltage) shall be measured with

an electrometer or other suitable device having an input resistance of 10,000 megohms or greater. Recovery

voltage shall be read at the maximum voltage within a 15 minute period. The dielectric absorption shall be computed

from the following formula.

Where:

d = Percent dielectric absorption.

V1 x 100

V1 = Maximum recovery voltage.

d = 

V2= Charging voltage.

For an alternate production test method see figure 1.