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

dc rated dc voltage or 100 volts dc, whichever is less (2 percent).

R1 and R2

1,000 ohms �20 percent. (This is not critical.)

5 ohms �1 percent.

10,000 megohms, minimum.

Suggest use of 1230A GR electrometer or equivalent set to 10,000 megohms range input resistance.

NOTES:

1. Charge for 5 minutes 10 seconds with switch in position 1.

2. Switch in position 2 for 5 seconds �0.5 second.

3. Switch in position 3 for 1 minute.

4. After 1 minute read recovery voltage and compute as a percentage of charge voltage.

5. Switch to position 4, discharge and remove.

FIGURE 1. Typical production dielectric absorption test method.

4.7.18 Stability at low and high temperatures (see 3.22). Capacitors shall be placed in a chamber maintained at

-65�C +0�C, -5�C or -55�C +0�C, -5�C (as applicable, see 3.1), and a potential equal to the dc rated voltage shall be

applied at this condition for 48 hours 4 hours. The air within the conditioning chamber shall be circulated. Before

capacitors are moved from the conditioning chamber, capacitance shall be measured at the applicable low

temperature (see 3.1) as specified in 4.7.9. Capacitance shall then be measured at the following temperature as

specified in 4.7.9. (The measurement at each temperature shall be recorded when two successive readings taken at

5-minute intervals indicate no change in capacitance.)

+25�C 5�C

High ambient test temperature (see 3.1)

+25�C 5�C

After the test, capacitors shall be visually examined for evidence of breakdown, arcing, open-circuiting and

short-circuiting, and other visible mechanical damage.