Thermal resistance to ambient

Symbol
$T_{4\mu}$
Unit
K.m/W
Formulae
$T_{4ss}$without cyclic load variation (continuous load)
$T_{4ss} \left(\frac{T_{4d} \left(1 - \mu\right)}{T_{4ss}} + \mu\right)$with cyclic load variation
$T_{4ss} \left(\mu_{w} + \frac{T_{4w} \left(1 - \mu_{w}\right)}{T_{4ss}}\right) \left(\frac{T_{4d} \left(1 - \mu\right)}{T_{4ss}} + \mu\right)$with daily and weekly cyclic load variations
$T_{4ss} \left(\mu_{w} + \frac{T_{4w} \left(1 - \mu_{w}\right)}{T_{4ss}}\right) \left(\mu_{y} + \frac{T_{4y} \left(1 - \mu_{y}\right)}{T_{4ss}}\right) \left(\frac{T_{4d} \left(1 - \mu\right)}{T_{4ss}} + \mu\right)$with daily, weekly and yearly cyclic load variations
Related
$\mu$
Used in
$\Delta \theta_{c}$
$\theta_{e}$