The equation for Thermal Resistance is:

with

• T being the temperature difference (in Kelvin)
• q being the Heat flow rate (in W/m2)
• L being the thickness of the material (in metres)
• k being the Thermal conductivity (in W/(mK) Watts per metre kelvin)

Whether you use temperature and q, kelvin / (Watts x metres^2) => (metres^2 x Kelvin) / Watts or L and k, metres / (Watts / (metre x kelvin)) => (metres^2 x Kelvin) / Watts

they both give you (metres^2 x Kelvin) / Watts. This makes sense as (m^2 x K) / W is the units for thermal resistance.

So why do datasheets for electronic components give thermal resistance as °C/W? I understand °C/W likely means for every Watt of power wasted by the device, the device will rise by that temperature. But how can it have two different units?

Is 8°C/W the same as 8 (m^2 x K) / W?

The equation for thermal resistance R is:

$$R=\frac{\Delta T}{q}=\frac{L}{k}$$

with

• T being the temperature difference (in kelvins)
• q being the heat flow rate (in W/m²)
• L being the thickness of the material (in metres)
• k being the thermal conductivity (in W/(mK), watts per metre kelvin)

Whether you use:

• temperature and q, kelvin / (watts × metres²) ⇒ (metres² × kelvin) / watts or

• L and k, metres / (watts / (metre × kelvin)) ⇒ (metres² × kelvin) / watts,

you obtain (metres² × kelvin) / watts. This makes sense, as (m² × K) / W is the units for thermal resistance.

So why do datasheets for electronic components give thermal resistance with units of °C/W? I understand °C/W likely means for every watt of power dissipated by the device, the device heats up by that temperature. But how can this parameter have two different units?

Is 8°C/W the same as 8 (m² × K) / W?