Convert Degree Fahrenheit per watt to Degree Celsius per milliwatt

Convert Degree Fahrenheit per watt (°F/W) to Degree Celsius per milliwatt (°C/mW) instantly and accurately.

Degree Fahrenheit per watt (°F/W)
Degree Celsius per milliwatt (°C/mW)

Conversion Formula

°C/mW = °F/W × 0.0005555555556

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 Degree Celsius per milliwatt

The degree Celsius per milliwatt (°C/mW) equals exactly 1000 K/W since 1 mW = 10⁻³ W and 1 °C = 1 K. Widely used in low-power semiconductor datasheets for characterising junction-to-ambient resistance: small-signal transistors, LEDs, photodiodes, and SMD resistors typically show RθJA of 50-500 °C/mW. A device at 200 °C/mW dissipating 5 mW rises 1 °C. 1 °C/mW = 1000 K/W = 1 kK/W.

Quick Reference Table

Degree Fahrenheit per watt (°F/W)Degree Celsius per milliwatt (°C/mW)
1 °F/W0.000555556 °C/mW
2 °F/W0.00111111 °C/mW
5 °F/W0.00277778 °C/mW
10 °F/W0.00555556 °C/mW
25 °F/W0.0138889 °C/mW
50 °F/W0.0277778 °C/mW
100 °F/W0.0555556 °C/mW

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