IEC61709 E factor

medini_1058885707

medini does contain all formulas exactly as given in IEC61709. The π E Factor is in that standard only used in the formula for the case of the Generic Stress Model. That is supported by medini - i.e. the user has to select the appropriate environment: Dependening on the selected environment the appropriate value is used: For all component-type specific formulas the IEC61709 does not have the pi_E factor included and the formulas for lambda are more simplified (as shown below for transistors&diodes): As you can see above for transistors only the voltage & temperature factors are taken into account (and for diodes only temperature factor). And yes, in case you use parts designed only for a low stress environment (E1) and apply them in a high-stress environment (E3), you either have to prove their application is systematically and sufficiently protected against the stress or you may need to apply pi_E with a value of 2 or 4 (if the base failure rates have also bee determined for E1 environment only). Examples of when the E-factor might be relevant: -the design of the equipment (i.e. the availability and effectiveness of protection measures against external stresses) and usage environment. Here also you could look up more details in 61709: 2. The source for the base failure rates may also reveal under which conditions these failure rates have been determined (Note, 61709 does not contain the base failure rates but refers to use other handbooks like SN29500, field statistics, supplier data sheets, ... as a source for base failure rates)