This white paper explores the 85°C/85% RH accelerated life test, its impact on RH sensors, and ultimately how to address conflicts when the same design needs both 85°C/85% tests and RH sensors.
Consumers expect their electronic systems to last for a specific period of time, either because they have historically, or because the manufacturer provided a specific lifetime warranty. Enabling a system to operate beyond these expectations gives consumers confidence in the product and its manufacturer, and can engender brand loyalty. In products such as heating, ventilation and air-conditioning systems or vehicles, consumers expect product lifetimes to extend beyond 10 years, a phenomenon that is ultimately putting pressure on system developers to ensure reliable designs – normally through extended testing.
The need for improved reliability of systems has also driven adoption of relative humidity (RH) sensors that provide information about the moisture content in the air. Moisture in the environment can create short circuits between electrical components, influence other components such as CO2 or pressure sensors, or can simply change the efficiency of systems designed to control air quality and temperature. The most common types of humidity sensors leverage a polymer to interact chemically with moisture in the air, and then quantify the moisture absorption based on a resistance or capacitance value. While these types of RH sensors are ultimately effective at the task of evaluating moisture content in a system, this chemical interaction with the environment leads to unique challenges compared to other components, especially when it comes to accelerated life testing.