Convert Degree Fahrenheit per watt to Second-degree Fahrenheit per BTU

Convert Degree Fahrenheit per watt (°F/W) to Second-degree Fahrenheit per BTU (s·°F/BTU) instantly and accurately.

Conversion Formula

s·°F/BTU = °F/W × 1055.055853

About Degree Fahrenheit per watt

The degree Fahrenheit per watt (°F/W) equals exactly 5/9 K/W ≈ 0.5556 K/W. It appears in US power electronics datasheets and legacy JEDEC thermal specifications where junction-to-case resistance is reported in °F/W rather than °C/W or K/W. A device rated 5 °F/W has R = 5 × 5/9 ≈ 2.78 K/W. 1 °F/W = 5/9 K/W.

About Second-degree Fahrenheit per BTU

The second-degree Fahrenheit per BTU (s·°F/BTU) equals (5/9)/1055.05585262 K/W ≈ 5.265 × 10⁻⁴ K/W. Used in US aerospace and nuclear engineering where thermal transient analyses express power as BTU/s and temperature in °F, e.g. rocket engine heat rejection and reactor coolant loop calculations. 1 s·°F/BTU ≈ 5.265 × 10⁻⁴ K/W.

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