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

FIGURE 2. Seal test enclosure.

4.5.17 EMI/RFI shielding (when specified, see 3.1 and 3.20).

4.5.17.1 EMI/RFI shielding case grounding (when specified, see 3.1) (see 3.20). The switch shall be mounted by

its normal mounting means to an electrically conductive panel. The resistance shall be measured from the RFI

shielding on the switch (plated surface) to the mounting panel. The measurement shall be made using an open

circuit voltage of 6 V dc and a maximum current of 10 mA.

4.5.17.2 EMI/RFI shielding efficiency (when specified, see 3.1) (see 3.20). Switches shall be tested utilizing a test

setup or equivalent as shown on figure 3 and measurements shall be made as follows:

a. With the door open and the antenna in the "initial setup" position, establish a test level over the 200 MHz to 1

GHz range so that the received signal level is at least as many dB above the RF ambient level as that of the

shielded enclosure attenuation.

b. Record the received signal level and the signal generator output levels for the following test frequencies: 200

Hz, 225 Hz, 250 Hz, 275 Hz, 300 Hz, 325 Hz, 350 Hz, 375 Hz, 400 Hz, 600 Hz, 800 Hz, and 1,000 MHz.

c. Move the antenna to the final test positions, close the door and with an RF-tight blank panel between the

antenna, measure the integrity of the enclosure by setting the signal generator to the same output and record

the received signal level for each frequency used in 4.5.17.2b. The shielded enclosure attenuation is then

calculated using the following equation:

Attenuation (dB) = 20 log

Where E1 is the receiver reading in 4.5.17.2b, and E2 is the receiver reading in 4.5.17.2c.

d. Mount the test switch in the blank panel with the rear of the switch outside of the shielded enclosure (toward

the signal generator antenna). The switch shall be mounted as it would be for normal installation using the

mounting hardware supplied or recommended. Repeat the measurements in 4.5.17.2c and calculate the

shielding attenuation of the switch using the new receiver readings and the following formula:

Attenuation (dB) = 20 log

Where E1 is the receiver reading in 4.5.17.2b, and E3 is the receiver reading in 4.5.17.2d.

4.5.18 Acceleration (when applicable, see 3.1 and 6.2.2) (see 3.21). Switches shall be subjected to an

acceleration force of 20G attained within 2 minutes. The force shall be maintained for 1 minute in each direction

along each of its three mutually perpendicular axes. The switches shall be monitored for opening of closed contacts

and closing of open contacts with a circuit utilizing a pilot lamp. Half of the units shall be tested with the actuating

means in one position and the other half of the units shall be tested with the actuating means in an alternate position.