Why Can Electronic Equipment Fail After a Period of Non-Operation?

PCB humidityEquipment reliability is typically measured by Mean Time Between Failure (MTBF) or failure probability vs. time, where time measures operation hours. When electronic equipment is not used, a user may switch the power off, expecting that next time the device is turned on, it will operate as before. Thus, the failure rate during non-operation is often assumed to be zero. However, in some cases, when a product is not used for a long period of time, it malfunctions when turned back on.

 

The main reason for failure of electronic devices after long periods of inactivity is humidity. Electronic components are sensitive to moisture. When exposed to moisture, components develop corrosion that may in some cases result in short circuits. The moisture content in the air depends on the relative humidity with higher relative humidity meaning higher moisture content.

 

Humidity is an issue for outdoor and naval equipment, as well as for datacenters and large storage facilities where humidity control is expensive.

 

The reason humidity causes fewer product failures during operation is that the heat generated inside the device packaging decreases the relative humidity, therefore reducing the amount of moisture.

 

There are common strategies to protect against humidity and moisture such as hermetic sealing of package, use of desiccants, dehumidifiers, or simply keep equipment in warm stand-by.

 

BQR in collaboration with its customers developed a unique model to calculate the reliability of electronic equipment, accounting for the relative humidity during non-operation time. This model is part of fiXtress 프로 – BQR’s reliability and MTBF prediction software.

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