Deratingfaktorer

Deratingfaktorer, or derating factors, are design parameters used to reduce the usable ratings of electrical components in order to improve reliability and lifespan under adverse environmental conditions. They are applied in electrical and electronic design to avoid operating components at their absolute maximum ratings.

The main drivers of derating are temperature and thermal conditions. As temperature rises, electrical performance can deteriorate and the risk of failure increases; therefore the permissible current, voltage, or power is reduced according to derating curves provided by manufacturers or standards. Other factors that can drive derating include altitude and reduced cooling, humidity, vibration and mechanical stress, voltage transients, aging, and cumulative wear. Derating is typically implemented by multiplying the component’s rating by a derating factor between 0 and 1, or by choosing a component with a higher nominal rating than the required load.

Applications span a range of components. For power semiconductors such as MOSFETs and IGBTs, derating ensures operation stays below the maximum junction temperature, often guided by thermal models and safe operating area limits. For resistors, derating accounts for higher ambient temperatures by lowering usable power from the nominal rating; for capacitors, derating helps avoid excessive voltage or ripple during surges; for LEDs, derating prolongs life by limiting driving current under higher temperatures.

Practice and standards emphasize documenting derating strategies in designs. Manufacturers publish derating guidelines, and engineers incorporate thermal management, margin analysis, and reliability assessments (including aging models) to set appropriate factors. Deratingfaktorer thus contribute to predictable performance and longer service life in electronic systems.