MIL-PRF-87217 Capacitors, Fixed, Supermetallized Plastic Film Dielectric, Direct Current For Low Energy, High Impedance Applications, Hermetically Sealed In Metal Cases, High Reliability, General Specification ForThis specification covers the general requirements for high reliability, supermetallized plastic film dielectric, fixed capacitors, hermetically sealed in metal cases. Capacitors covered by this specification have a failure rate \(FR\) level established in accordance with MIL-STD-690. This FR level is established at a 90-percent confidence level and maintaned at a 10-percent producer\'s risk and, unless otherwise specified \(see 3.1\), is based on MIL-PRF-83421 life tests performed at maximum rated voltage at maximum rated temperature.

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MIL-PRF-87217A

4.7.4 High impedance temperature and voltage ramp (see figure 1).

a. Each part shall be connected with 1-10 megohms in series.

b. Parts shall be temperature ramped for 5 cycles from 25 C to 100 C, to -55 C, and to 25 C with an equally

timed stay at the temperature extremes (100 C/-55 C).

c. Parts shall be voltage ramped during the temperature extremes only. A 0 volt to 30 volt ( 10%) ramp in 30

minutes ( 3 minutes) shall be applied to the RC circuit. After the capacitor reaches 30 volts charge, the

capacitors will be linearly discharged within 30 minutes 3 minutes. When the voltage reaches 200

millivolts, the voltage ramp to 30 volts is repeated (3 ramps during each exposure at the temperature

extremes). For capacitance values above 10 microfarads, use a 60 minute 6 minute ramp to 30 volts.

d. Parts shall be monitored for high leakage current continuously, or scanned at a minimum of once every 0.5

seconds, during the 5 temperature cycles. Noise shall be limited to 6 mV, peak.

e. A permanent record of current excursions in excess of .05 A shall be maintained.

STABILIZE CAPACITORS AT TEMPERATURE EXTREMES AND VOLTAGE RAMP 3 TIMES

(0 TO 30 V dc) 10% AND (30 TO 0 V dc) 10% WHILE MONITORING FOR LEAKAGE CURRENT

FIGURE 1. Voltage and temperature ramp test.

4.7.5 Insulation resistance (see 3.9). Capacitors shall be tested in accordance with method 302 of MIL-STD-202.

The following details shall apply:

a. Test potential: Rated voltage, unless otherwise specified (see 3.1).

b. Points of measurement: Between terminals at the applicable specified temperatures (see 3.1), and at

25 C 3 C.

c. Charge time 5 minutes maximum; however, for capacitance values greater than 1.0 F, an additional 1

minute per F is permitted.