MIL-R-19365 Resistor, Adjustable, Wirewound, PowerThis specification covers power, adjustable, wirewound, resistors for use in electrical, electronic, communication, and associated equipment. These resistors have a resistance range of 1 ohm to 15,000 ohms, inclusive, and a resistance tolerance of ┬▒5 percent. The power ratings cover a range of 11 watts to 210 watts, inclusive. These power ratings are applicable only when the maximum resistance is engaged in the circuit. When only a portion of the resistance element is engaged, the power rating is reduced in approximately the same proportion as the resistance.

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MIL-R-19365E

TABLE IX. Group B sampling plan.

Lot size

Sample size

2 to 5

6 to 50

51 to 90

91 to 150

151 to 280

281 to 500

501 to 1,200

1,201 to 3,200

3,201 to 10,000

10,001 to 35,000

35,001 and over

100%

4.6.4 Inspection of preparation for delivery. Sample packages and packs and the inspection of the preservation and packaging, packing, and marking for shipment and storage shall be in accordance with the requirements of section 5 and the documents specified therein.

4.7 Methods of inspection.

4.7.1 DC resistance (see 3.7). The dc resistance shall be measured in accordance with method 303 of

MIL-STD-202 and as specified in 4.7.1.1 and 4.7.1.2. The following details and exceptions shall apply:

a. Measuring apparatus: Different types of measuring test equipment (multimeters, bridges, or equivalent) are permitted to be used on the initial and final readings of this test, provided the equipment is the same style, model, or it can be shown that the performance of the equipment is equivalent or better.

b. Test voltage: Measurements of resistance shall be made by using a dc potential resulting in not more than 1 percent of rated wattage (see 3.6). The voltage used for the initial measurement shall be used for all subsequent measurements.

4.7.1.1 Total (see 3.7.1). The dc resistance shall be measured as specified in 4.7.1 between the two fixed end terminals. For the initial tolerance determination, the total resistance shall be measured with the adjustable terminal removed from the resistor.

4.7.1.2 Maximum engageable (see 3.7.2). The dc resistance shall be measured as specified in 4.7.1, between each fixed end terminal and the adjustable terminal, with the latter positioned farthest from the fixed end terminal, while still engaging the bare resistance wire.

4.7.2 Visual and mechanical examination. Resistors shall be examined to verify that the materials, design, construction, physical dimensions, marking and workmanship are accordance with the applicable requirements (see 3.1, 3.3 to 3.5 incl., and 3.19 to 3.23 incl.).

4.7.3 Resistance temperature characteristic (3.8).

4.7.3.1 Qualification inspection. Resistors shall be tested in accordance with method 304 of MIL-STD-202 . The following detail and exception shall apply:

a. Test temperatures: As specified in table X.

b. Measurement at end of each period: Total resistance shall be measured as specified in 4.7.1.1, at the temperature maintained during the period.