MIL-STD-202 Test Methods
The test-method standard behind electronic and electrical component qualification
MIL-STD-202 is not a product specification and not something a power supply is qualified to. It is a numbered library of standardized test methods for small electronic and electrical component parts: capacitors, resistors, connectors, and, importantly for Abbott, transformers and inductors. When a performance specification needs a component screened for thermal shock, moisture, vibration, or shock, it points to a MIL-STD-202 method number rather than redefining the test each time.
MIL-STD-202 defines exactly how each of those tests is run: the setup, the conditions, the sequence, and the measurements. What it does not do is set the pass or fail limits. Those come from the governing specification, which invokes the method and assigns the acceptance criteria. The current revision is MIL-STD-202H (2015, with Notice 1 in 2020).
For Abbott, MIL-STD-202 matters because it is the how-to behind our magnetics qualification. MIL-PRF-27 calls out MIL-STD-202 method numbers for the environmental screening of transformers and inductors, so MIL-STD-202 defines precisely how those tests are performed. This page explains what MIL-STD-202 is, how it is invoked, and which methods stand behind Abbott’s MIL-PRF-27 magnetics.
What MIL-STD-202 Is, and Is Not
The distinction matters when you read a requirement or a datasheet:
| MIL-STD-202 is | MIL-STD-202 is not |
|---|---|
| A standardized library of component test methods, referenced by number (for example Method 107, thermal shock). | A product specification. You do not “qualify a power supply to MIL-STD-202.” |
| The definition of how a test is set up, conditioned, and measured. | A source of pass or fail limits. The governing spec sets the acceptance criteria. |
| Invoked by performance specifications such as MIL-PRF-27, which assign the method, condition, and limits. | Usually listed on individual product datasheets; it is invoked indirectly through the part specification. |
| A component-level standard, for the parts inside an assembly. | An equipment-level environmental standard. That role belongs to MIL-STD-810, MIL-STD-167, and MIL-DTL-901. |
The MIL-STD-202 Method Groups
MIL-STD-202 organizes its methods into three groups. The examples below are the ones most relevant to power components and magnetics.
| Method group | Covers | Examples relevant to power components |
|---|---|---|
| 100 series, environmental | Environmental exposure and survivability | Salt atmosphere (101), immersion (104), barometric pressure (105), moisture resistance (106), thermal shock (107), seal (112) |
| 200 series, physical and mechanical | Mechanical stress and construction integrity | Vibration, high frequency (204), acceleration (212), shock, specified pulse (213), solderability (208), terminal strength (211) |
| 300 series, electrical | Electrical characteristics and integrity | Dielectric withstanding voltage (301), insulation resistance (302), DC resistance (303) |
The MIL-STD-202 Methods MIL-PRF-27 Invokes
MIL-PRF-27 Table I calls out specific MIL-STD-202 methods for the environmental screening of transformers and inductors. These are the tests that stand behind an Abbott MIL-PRF-27 magnetics qualification:
| Method | Test | What it verifies for a transformer or inductor |
|---|---|---|
| 107 | Thermal shock | Survival of rapid transitions between temperature extremes without cracking or seal failure |
| 104 | Immersion | Seal integrity against water ingress (applied to Grades 4 and 5) |
| 106 | Moisture resistance | Performance and insulation integrity after repeated humidity cycling |
| 204 | Vibration, high frequency | Mechanical integrity of the windings, core, and leads under vibration |
| 213 | Shock, specified pulse | Survival of defined mechanical shock pulses |
| 101 | Salt atmosphere | Corrosion resistance, when specified (applied to Grades 4 and 5) |
| 301 / 302 / 303 | Dielectric withstanding voltage, insulation resistance, DC resistance | Electrical integrity of the windings and the insulation system |
How the invocation works: MIL-PRF-27 assigns each method a condition and a pass or fail limit, and the applicable methods depend on the transformer or inductor grade (construction) and class (temperature). MIL-STD-202 supplies only the procedure. Revisions matter too: MIL-STD-202H is current, but a part or assembly qualification cites the revision in effect at the time of test, so you may see MIL-STD-202G referenced on older documentation. Confirm the method, condition, and revision your requirement invokes. See the MIL-PRF-27 guide for how grade and class set the screening.
How MIL-STD-202 Relates to Abbott Products
Abbott’s MIL-PRF-27 transformers and inductors are built and screened to the MIL-STD-202 methods that MIL-PRF-27 Table I invokes, so the thermal-shock, moisture, vibration, shock, and salt performance behind a QPL-27 designation traces directly to these standardized procedures. Because MIL-STD-202 is a component-level standard, it is invoked through the part specification rather than listed on each product line, and it works alongside the equipment-level standards, MIL-STD-810 for environment, MIL-STD-167 for vibration, and MIL-DTL-901 for shock, that qualify a complete power supply.
Abbott designs and builds its own magnetics in house, so we control the construction and the insulation system that these methods verify. That is what lets us qualify standard designs to MIL-PRF-27 and adapt them to a program’s specific grade, class, and test requirements from a proven baseline.
Need a transformer or inductor screened to specific MIL-STD-202 methods, or a MIL-PRF-27 magnetic qualified to your grade and class? Send us the methods, conditions, and limits your program invokes. Our engineers will identify a standard or custom magnetic to match. Contact us or complete the power supply design form.