MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第24页

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MIL-STD-883F

6.4 Changes from previous issue

. The margins of this standard are marked with asterisks where changes from the

previous issue were made. This was done as a convenience only and the Government assumes no liability whatsoever for

any inaccuracies in these notations. Bidders and contractors are cautioned to evaluate the requirements of this document

based on the entire content irrespective of the marginal notations and relationship to the last previous issue.

CONCLUDING MATERIAL

Custodians: Preparing activity:

Army - CR DLA -CC

Navy - EC

Air Force - 11 (Project 5962-2024)

NASA – NA

DLA-CC

Review activities:

Army - AR, MI, SM

Navy – AS, CG, MC, OS, SH, TD

Air Force - 19, 99

Note: The activities listed above were interested in this document as of the date of this document. Since organizations and

responsibilities can change, you should verify the currency of the information above using the ASSIST Online

database at www.dodssp.daps.mil

MIL-STD-883F

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MIL-STD-883F

METHOD 1001

1 May 1968

METHOD 1001

BAROMETRIC PRESSURE, REDUCED (ALTITUDE OPERATION)

1. PURPOSE

. The barometric-pressure test is performed under conditions simulating the low atmospheric pressure

encountered in the nonpressurized portions of aircraft and other vehicles in high-altitude flight. This test is intended primarily

to determine the ability of component parts and materials to avoid voltage breakdown failures due to the reduced dielectric

strength of air and other insulating materials at reduced pressures. Even when low pressures do not produce complete

electrical breakdown, corona and its undesirable effects, including losses and ionization are intensified. The simulated

high-altitude conditions of this test can also be employed to investigate the influence on components' operating

characteristics, of other effects of reduced pressure, including changes in dielectric constants of materials, and decreased

ability of thinner air to transfer heat away from heat-producing components.

2. APPARATUS

. The apparatus used for the barometric-pressure test shall consist of a vacuum pump and a suitable

sealed chamber having means for visual observation of the specimen under test when necessary, a suitable pressure

indicator to measure the simulated altitude in feet in the sealed chamber, and a microammeter or oscilloscope capable of

detecting current over the range from dc to 30 megahertz.

3. PROCEDURE

. The specimens shall be mounted in the test chamber as specified and the pressure reduced to the

value indicated in one of the following test conditions, as specified. While the specimens are maintained at the specified

pressure, the specimens shall be subjected to the specified tests. During this test and for a period of 20 minutes before, the

test temperature shall be 25°C ±10°C. The device shall have the specified voltage applied and shall be monitored over the

range from atmospheric pressure to the specified minimum pressure and return for any device malfunctions. A device which

exhibits arc-overs, harmful coronas, or any other defect or deterioration which may interfere with the operation of the device

shall be considered a failure.

Test condition Pressure, maximum Altitude

Inches of mercury mm of mercury Feet Meters

A 17.3 439.00 15,000

4,572

B 8.88 226.00 30,000

9,144

C 3.44 87.00 50,000

15,240

D 1.31 33.00 70,000

21,336

E 0.315 8.00 100,000

30,480

F 0.043 1.09 150,000

45,720

G 9.436 x 10

-8

2.40 x 10

-6

656,000

200,000

3.1 Measurement

. The device shall be connected for measurement and have the specified voltages applied during the

entire pump-down cycle. The terminals to which the maximum voltage (see 4c.) is applied shall be monitored with a

microammeter or oscilloscope for corona currents in the range from dc to 30 megahertz. Provision shall be made for

calibrating the current flow in the test circuit minus the device under the applicable test condition to insure that test readings

are characteristic of the device under test.