MIL-PRF-22710 Switches, Code Indicating Wheel \(Printed Circuit\), Thumbwheel And Push-Button, General Specification ForThis specification covers the general requirements for illuminated and non-illuminated, thumbwheel \(see 6.4.1\), and push-button, printed circuit rotary switches having unsealed and sealed modules and the associated hardware. These switches are designed for low power alternating current \(ac\) and direct current \(dc\) switching applications for use in electronic and communication equipment. Procurement of switches and mounting hardware will require additional data, giving detailed electrical and mechanical requirements, tolerances, and applicable additions and exceptions to the general requirements and tests specified herein \(see 6.2\).

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MIL-PRF-22710H

3.20 EMI/RFI shielding (when specified, see 3.1 and 4.5.17). When switches are tested as specified in 4.5.17.1,

the resistance measurement shall not exceed 1 ohm. When switches are tested as specified in 4.5.17.2, the

shielding attenuation shall be not less than 60 dB from 200 MHz to 1,000 MHz, unless otherwise specified (see 3.1).

3.21 Acceleration (when applicable, see 3.1). When switches are tested as specified in 4.5.18, there shall be no

opening of closed contacts, or closing of open contacts, and there shall be no mechanical or electrical damage.

3.22 Sand and dust (when applicable, see 3.1). When switches are tested as specified in 4.5.19, there shall be no

evidence of physical damage, and the switches shall be mechanically and electrically operative at the conclusion of

the test. For thumbwheel-operated switches, the torque shall not change in excess of 100 percent of the initial

measured value. For push button operated switches, the torque shall not change in excess of 25 percent of the initial

measured value.

3.23 Explosion (when applicable, see 3.1). When switches are tested as specified in 4.5.20, there shall be no

explosion within the test chamber, whether or not explosion occurs within the switch.

3.24 Salt spray (corrosion). When switches are tested as specified in 4.5.21, there shall be no evidence of

excessive corrosion. Excessive corrosion is defined as corrosion which interferes with the electrical or mechanical

performance, or, in the case of plated metals, corrosion which has passed through the plating and exposed the base

metal. After the test, mounting hardware shall be readily removable.

3.25 Life (rotational). When switches are tested as specified in 4.5.22, they shall be electrically and mechanically

operative during and after the test. During the test, there shall be no evidence of intermittent electrical operation.

The specified contact-sequential pattern shall be maintained throughout the test. At the conclusion of the test, the

average rotational torque or operating force (see 3.8) shall not have changed more than +30 percent from the initial

value (see 3.1). After the test, there shall be no evidence of broken, deformed, displaced, or loose parts.

3.25.1 Switch section alignment (applicable to nonshorting switches where more than one switch section is

operated by a common shaft, see 3.1). When switches are tested as specified in 4.5.22.1, during the period of

monitoring for switch section alignment, the identical circuits, in the first and last sections of the assembly, shall both

be open at the same time for some duration while switching from one position to the next.

3.26 Life, low level switching. When switches are tested as specified in 4.5.23, the faults permissible shall not be

exceeded (see 3.1 and 6.2.2). After the test, there shall be no evidence of broken, deformed, displaced, or loose

parts and the contact resistance, insulation resistance, and dielectric withstanding voltage shall be in accordance with

the requirements of 3.5, 3.15, and 3.18, respectively.

3.27 Solderability. When switches or printed circuit boards are tested as specified in 4.5.24, 95 percent of the total

length of the fillet, which is between the standard wrap wire and the terminal, shall be tangent to the surface of the

terminal being tested and shall be free from pinholes, voids, etc. However, a ragged or interrupted line at the point of

tangency between the fillet and the terminal under test shall be considered a defect. After the test, there shall be no

evidence of fracture, loosening of parts, or any other mechanical failure of the switches or printed circuit boards.

3.28 Marking. Switches shall be marked in accordance with MIL-STD-1285 with the following information:

a. PIN, when applicable, or type designation with manufacturer's PIN.

b. Switch manufacturer's name, trademark, or code symbol, and date code.

c. When 3.28a is not applicable, the manufacturer's PIN, the Government drawing number, or prime contractor's

number shall be marked on the unit package.

d. Terminal identification (see 3.1).

3.28.1 Indicator ring. Unless otherwise specified, the marking of the applicable legend shall be in accordance with

3.29 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally

preferable materials shall be used to the maximum extent possible provided that the material meets or exceeds the

operational and maintenance requirements, and promotes economically advantageous life cycle costs.