MIL-PRF-28776 Relays, Hybrid, Established Reliability, General Specification ForThis specification establishes the general requirements for relays that use a combination of solid state circuit input elements functioning with an electro-mechanical relay that performs the switching functions associated with control system applications \(see 6.1\). These relays are designed to operate in low and medium power switching circuits with contact ratings up to 1 ampere alternating current \(ac\) or direct current \(dc\). The failure rate level is established at a confidence level of 90 percent for qualification and 60 percent for maintenance of qualification based on 100,000 cycles at +125┬░C under rated load conditions specified herein. Excludes time delay relays. CAUTION: The use of any coil voltage less than the rated coil voltage will compromise the operation of the relay. CAUTION: Pick-up, hold, and dropout voltages are for test purposes only and are not to be used as design criteria. For additional application and caution information, see 6.1.

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MIL-PRF-28776F

4.8.21 Resistance to solvents (see 3.26). Relays shall be tested in accordance with method 215 of MIL-STD-202.

The following details and exceptions shall apply:

Portion to be brushed: All marking.

Optional procedure for solvent d is not applicable.

Specimens to be tested: One sample shall be tested with each solvent solution. For qualification

inspection, samples in excess of the available number of solvents shall be exempt from test. For group C

testing, two additional samples shall be selected. The additional samples may be electrical rejects from

group A2.

Examination: Specimens shall be examined for legibility of marking.

4.8.22 Voltage transients (see 3.27). Samples shall be subjected to the transient susceptibility tests as follows.

Rated supply voltage shall be applied to the relay coil circuit. For a period of 60 seconds minimum at 10 ms +1 ms

intervals, repetitively apply on the input, a voltage transient pulse with an amplitude as specified in 4.8.22a and

4.8.22b and a pulse duration of 100 s �10 s. Rise/fall time of pulse leading edge shall be 1 �s maximum with

overshoots not to exceed 5 percent. Contacts shall be monitored by an acceptable means approved by the qualifying

activity. The contact loads shall be 10 mA maximum at 6 V dc maximum or peak ac. The pulse amplitude shall be as

Specified turn-off voltage shall be applied. A series of transient voltage pulses with amplitude equal to the

maximum control signal voltage, or an equivalent voltage to produce the maximum control signal current,

as applicable, shall then be applied (see figure 11, configuration A). The relay contacts shall not change

state.

Specified turn-on voltage, or an equivalent voltage to produce the specified turn-on current, as applicable,

shall be applied. A series of transient pulses with voltage amplitude equal to -2.0 V dc �0.1 V dc shall then

be applied (see figure 11, configuration B). For FET driven hybrid relays, a current limiting resistor may be

used. The relay contacts shall not change state.

FIGURE 11. Voltage transients test waveforms.