MIL-PRF-22097 Resistors, Variable, Nonwirewound, Adjustment Type, General Specification ForThis specification covers the general requirements for multi-turn lead screw actuated and single turn nonwirewound, variable resistors with a contact bearing uniformly over the entire surface of the entire resistive element, when positioned by the actuator. These resistors are capable of full load operation \(where maximum resistance is engaged\) at a maximum ambient temperature of 70 Degrees C and 85 Degrees C, and are capable for continuous operation when properly derated, at a maximum temperature of 125 Degrees C and 150 Degrees C \(see figure 1\). These resistors have a resistance of ┬▒10 percent \(see 3.1\).

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MIL-PRF-22097J

3.12.3 Stop (applicable only to single turn units, unless otherwise specified). When resistors are tested as

specified in 4.7.7.3, they shall withstand the stop torque specified (see 3.1), without damage to the contact arm or

stop.

3.13 Thermal shock. When resistors are tested as specified in 4.7.8, the change in total resistance shall not

exceed the applicable value specified in table I. The change in setting stability shall not exceed 2 percent for

characteristics A, and 1 percent for characteristic C and characteristic F. There shall be no electrical discontinuity or

evidence of mechanical damage.

3.14 Resistance temperature characteristic. When resistors are tested as specified in 4.7.9 and 4.7.9.1, the

resistance temperature characteristic, at each of the test temperatures, referred to an ambient temperature of 25 C,

shall not exceed the applicable value specified in table I.

3.15 Moisture resistance. When tested as specified in 4.7.10, resistors shall meet the following requirements:

Total resistance:

Change shall not exceed the applicable value specified in table I.

Insulation resistance:

Shall not be less than 100 megohms.

Visual inspection:

There shall be no evidence of mechanical damage.

3.16 Shock (specified pulse). When resistors are tested as specified in 4.7.11, the change in total resistance shall

not exceed the applicable value specified in table I. The change in setting stability shall not exceed 2 percent for

characteristic A, and 1 percent for characteristic C and characteristic F. There shall be no electrical discontinuity or

evidence of mechanical damage.

3.17 Vibration, high frequency. When resistors are tested as specified in 4.7.12, there shall be no electrical

discontinuity, and resistors shall meet the following requirements:

Change shall not exceed 2 percent for characteristic A, and 1 percent for

Setting stability:

characteristic C and characteristic F.

Change shall not exceed the applicable value specified in table I.

Total resistance:

Operating torque:

Shall not exceed 150 percent of the specified operating torque (see 3.1).

Visual inspection:

There shall be no evidence of mechanical damage.

3.18 Salt spray (corrosion). When resistors are tested as specified in 4.7.13, there shall be no appreciable

corrosion.

3.19 Resistance to soldering heat (applicable to terminal types P, S, W, X, and Y only). When resistors are tested

as specified in 4.7.14, the change in total resistance shall not exceed the applicable value specified in table I. There

shall be no evidence of mechanical damage.