Environmental Exposure
Controlled temperature and humidity aging protocols evaluate package sealing integrity under prolonged climate stress. Executing a damp heat test involves exposing unpowered or powered sensor assemblies to eighty-five degrees Celsius and eighty-five percent relative humidity inside an environmental chamber. Thermal energy accelerates moisture diffusion through polymeric housing materials and adhesive bond lines.
Water vapor entry causes corrosion of internal metal traces and compromises electrical isolation resistance between conductor paths. Standards such as IEC 60068-2-78 define exposure durations ranging from two hundred forty hours to one thousand hours. Metrological evaluation measures sensor drift and insulation degradation at specified time intervals during testing.
Moisture Degradation
Moisture absorption alters the dielectric constant of internal potting compounds. Increased parasitic capacitance shifts bridge circuit resonance and alters transducer sensitivity calibration. Condensation on sensitive substrates creates leakage paths that degrade high-impedance measurement nodes.
Post-test verification inspects potting interfaces for delamination under microscopic examination.
Sensor Drift
Parametric tracking records zero-point shifts before and after chamber exposure. Zero-point drift exceeding maximum allowable drift limits signals enclosure seal failure. Humidity exposure also degrades bond wire connections through galvanic corrosion.
Failure criteria require strict adherence to pre-test functional specifications.
Qualification Threshold
Calibration checks perform insulation resistance measurements at five hundred volts direct current following chamber removal. Passing criteria demand insulation resistance above one hundred megohms. Product qualification halts when baseline offset drift exceeds allowable tolerances.
