3-01This specification covers 2 \(two\) hand-held Dynamic Microphones, with or without a self-contained transistor amplifier and different connectors for use in unique military equipment. A wall-mounted holder is also included.

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MIL-DTL-21393B

TABLE I. Standard/Service Conditions.

Standard

Service

Parameter

conditions

Room ambient (30� �10�C)

Temperature

Operating: (-40�C to 71�C),

Non-operating: (-57�C to +85�C)

Altitude

Normal ground

Operating (Sea level to 15,000 feet),

Non-operating (Sea level to 40,000 feet)

Vibration

None

Microphones should withstand random

excitation over the frequency range of 15

to 2,000 Hz, with energy density levels

specified by the appropriate figure and

table of MIL-STD-810, method 514,

procedure I. (see 4.6.3.7 and 6.3).

Humidity

Room ambient up to 90%

The microphones should withstand the

relative humidity

effects of humidities up to 100 %,

including conditions wherein

condensation takes place in and on the

equipment. The equipment should

withstand the above conditions during

operating and non- operating conditions.

4.2 Test equipment and inspection facilities. Test and measuring equipment and inspection facilities of

sufficient accuracy, quality, and quantity to permit performance of the required inspection shall be

established and maintained by the contractor. The establishment and maintenance of a calibration

system to control the accuracy of the measuring and test equipment [i.e., non-Government standard

(NGS) or Federal or Military standard] shall be in accordance with NCSL Z540-1 or equivalent.

4.3 First article inspection (microphone only). When required (see 6.2d), first article inspection shall

consist of all of the tests in table II.

4.3.1 Sample size. With the exception of the reliability test, 10 (ten) microphones shall be submitted

for first article inspection. For quantity related to reliability test, see table VIII. The units selected shall be

representative of "production configuration" in design, materials, construction and performance.

4.3.2 Inspection routine. The sample shall be subjected to the inspections specified in table II, in the

order shown. All sample units shall be subjected to the inspections of group I. The sample shall then be

divided equally into two groups of five (5) units each. One group shall be subjected to the group II

inspections, and the other group shall be subjected to group III inspections.

4.3.3 Failures. If one or more sample units fail to pass any group inspections, the sample lot shall be

considered to have failed.