Water, or moisture, forms the main cause of why electronics fail. When electronics are exposed to moisture, such as being splashed or dropped into liquid, or even from the vapor in high humidity environments, the electrical components in your device gets corroded and are no longer able to carry electrical currents.
Therefore, it is imperative that electronics devices are made to protect them against water, starting from the PCB and up to the actual device.
3 ways of protecting electronics from Moisture
- Coating
- Greases
- Gasket and Silicone
Let us dive deep into each method.
Coating
The most common protection method is using coatings, which come in two types:
Potting |
The PCB and its components are completely embedded in either epoxy resins or silicone/urethane gels. This covers the board substantially to prevent moisture from getting through, and provides a higher level of protection against heat, vibrations. Potting is most suited for rough conditions or high voltage devices. |
Conformal Coating |
A thin layer of coating is applied on the surface to cover the board and its components. Due to the thin layer, it is slimmer and lighter than a board protected via potting, hence it is suitable for small consumer or medical devices. |
Potting VS Conformal Coating
Grease
Grease is commonly applied to connectors, switches, relays, and moving parts.
Dielectric Grease |
Dielectric grease enhances insulation and safeguards electrical connections by forming a barrier against moisture. It repels water and does not get washed away. This type of grease is particularly useful in high-voltage situations, as it boosts the breakdown voltage between insulators when moisture is present. |
Conductive Grease |
Conductive grease prevents electrical connections from corroding by keeping water at bay. It finds application in roller bearings, preventing the accumulation of static charge and providing protection against moisture. However, it is not suitable for high-voltage applications. |
Silicone Grease |
Silicone grease is waterproof and well-suited for use in extreme environmental conditions. It can protect high-voltage electrical components and power cables. |
Gaskets and Silicone
After protecting the electronics on the PCB, the final step is to protect the device itself to prevent water from entering the circuitry. Rubber gaskets are used to seal the enclosure lids, and silicone is used to seal the openings for wiring passages.
With this multi-layered approach to protecting your electronics from PCB to the actual device, it boosts the level of moisture protection and keeps the device safe from liquids.