Moisture in Electronics

Electronic product failure caused by condensation can have a serious negative impact ranging from deteriorating brand loyalty to the more catastrophic when critical electronic components fail, resulting in injury or death. Even well sealed electronic products can have failures resulting from condensation. Understanding and proactively addressing the issue of moisture in the design process can be critical to preserving service life of the device.

Understanding why there is moisture in your device is the first step to protecting it. Ambient air containing moisture can be trapped in the device during assembly. A drop in temperature during shipping or storage can result in condensation within the device. Moisture ingress through permeable housing can also lead to condensation.

The best defense against moisture degradation is to choose materials with a low water vapor transmission rate and assemble the product in a humidity controlled environment. In addition, a very important step is to incorporate a desiccant into the device to adsorb any free moisture. There are several types of desiccants such as silica gel, molecular sieve, and calcium oxide, montmorillonite clays, and calcium sulfate – each having their own adsorption characteristics. Additionally, desiccants come in a variety of formats from simple packets to the more complex functional component formed from a desiccant loaded polymer.

Introduction of a desiccant should occur during the design phase. Having a knowledgeable application engineer, who asks the right questions and can size the desiccant correctly is necessary to ensure proper protection throughout the product’s intended service life.