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Switch Type: The basic snap action switches are qualified to MIL-PRF-8805/101 category I or category II.
Switch Capacity: Single pole double throw, double pole double throw or four pole double throw.
Switch Contact Schematic: The switch contact arrangements are either single break or double break. The double break allows two separate contact circuits or simply a single throw contact action.
See Figure 7.
Figure 7
SWITCH CONTACT IDENTIFICATION AND CIRCUIT SCHEMATIC
Switch Contact Resistance: 0.025 ohms maximum for silver with gold flash contacts.
Intermediate Current: The intermediate current test per MIL-PRF-22885F paragraph 3.35 is applicable to the gold flash silver contacts. 50,000 cycles minimum, 12,500 cycles at -40°C, 25,000 cycles at +23°C and 12,500 cycles at +71°C.
Low Level Life: The low level life test per MIL-PRF-22885F paragraph
3.36 is applicable to the gold plated contacts. 50,000 cycles with contacts loaded at 30 millivolts maximum DC or peak AC at 10 milliamperes maximum. 12,500 cycles at -40°C, 12,500 cycles at +23°C and 25,000 cycles at +71°C.
Dielectric Withstanding Voltage:
At sea level: 1,000 volts rms minimum, 60 Hz.
At 50,000 ft.: 400 volts rms minimum, 60 Hz.
Pushbutton Cap Display Styles: The pushbutton cap display is available in five versions, a four-way split screen, a horizontal split screen, two three-way split screens and a full screen display.
See Figure 8.
Figure 8
PUSHBUTTON CAP DISPLAY STYLES
LED Circuit Configurations: Each pushbutton cap contains 16 LEDs, four per quadrant, and all the electronics necessary for display illumination. The LED circuit is either a single circuit with one common, G (Style 1), or it is a horizontal split circuit with two commons, G and F (Style 2). Each quadrant has its own I/O labeled A, B, C and D according to the quadrant it illuminates. Each quadrant has its own independent electronic circuit consisting of four LEDs and the Driver, Dimming and Protection Circuit (DDPC) needed for their operation. The LED circuit can be either 28 VDC common anode (current sinking) or 28 VDC common cathode (current sourcing). Polarity is referenced with respect to commons G and F. See
Figure 9.
Figure 9
PUSHBUTTON CAP LED DIAGRAMS, VOLTAGE AND POLARITY
Quadrant Interconnection Circuit Styles: To reduce the number of input wires necessary to illuminate the display, the pushbutton cap is available with the quadrants A, B, C and D internally connected in various circuit styles so one input wire can activate one or more quadrants as shown in
Figure 10.
Figure 10
PUSHBUTTON CAP QUADRANT INTERCONNECTION CIRCUIT STYLES
Switch and LED Terminal Identification: The switch poles are denoted as position A for the 1-pole version, A and B for the 2-pole version and H, J, K and L for the 4-pole version. Switch contact terminals are marked 1, 2, 3 and 4. LED terminals are marked A, B, C, D, F and G. See
Figure 11.
Figure 11
SWITCH BODY AND LED TERMINAL IDENTIFICATION (BACK VIEW)
FIGURE 11 NOTES:
1. A and B identify the switch pole positions for the 1-pole and 2-pole versions and H, J, K and L identify the switch pole positions for the 4-pole version.
2. The switch contact terminals are identified as 1, 2, 3 and 4.
3. A, B, C and D identify the LED quadrant inputs and G and F identify the commons .
4. “SKT” identifies the socket side where input wires are inserted.
5. All solderless CTS QUIK-CONNECT™ plugs are supplied with sealing plugs P/N 18-215 or MS27488-20, which must be inserted into the unused locations. Example: A 4-pole, single-break, single-circuit pushbutton switch utilizing only three poles will require eight sealing plugs (see example above), one each in location 1, 2, 3 and 4 of the unused switch pole L, one each in location 4 of the three active poles H, J and K, and in location F of the LED circuit.
Power Consumption: The typical power consumption of the LED illuminated pushbutton cap at 23°C is 1.18 watts for 28 VDC units.
EMI/RFI Shielding Option: When specified, the shielding efficiency of the pushbutton switch is no less than 60dB for frequencies from 100MHz to 1000MHz. |
