Heat Sink Size Calculator

The below calculator is designed to calculate the heat sink size required for a given power and ambient conditions. This calculator assumes 1°C/W for the thermal resistance of the resistor body to the heat sink case.

Enter values below and the result will automatically be calculated.

Power dissipated in resistor:   W
Maximum resistance temperature:   °C
Maximum ambient temperature:   °C
Thermal resistance element to case:   °C/W
Required thermal resistance of external heat sink:   °C/W

Popular manufacturers

The table below offers some heat sink mountable resistor options we have available as well as some of their specifications:
Caddock MP915 Series 8.33°C/W 0.02Ω to 1kΩ ±1.0% (from 0.05Ω) -20 to +80 ppm/°C (from 0.5Ω) 15W TO-126 style
Caddock MP916 Series 7.81°C/W 0.01Ω to 0.019Ω ±5.0% 0 to +500 ppm/°C 16W TO-126 style
Caddock MP925 Series 5.00°C/W 5kΩ to 100kΩ ±1.0% -20 to +80 ppm/°C 25W TO-220 style
Caddock MP930 Series 4.17°C/W 0.02Ω to 4.99kΩ ±1.0% (from 0.05Ω) -20 to +80 ppm/°C (from 0.5Ω) 30W TO-220 style
Caddock MP9100 Series 1.50°C/W 0.05Ω to 100Ω ±1.0% -20 to +80 ppm/°C (from 0.5Ω) 100W TO-247 style
Isabellenhütte PBH Series 4°C/W 0.002Ω to 100Ω ±0.5% (from 0.01Ω) <50 ppm/°C 10W TO-247 style
Isabellenhütte PBV Series 3°C/W 0.0005Ω to 1Ω ±0.5% (from 0.0015Ω) <30 ppm/°C (from 0.01Ω) 10W Non-standard
Isabellenhütte A-H2 Series 3°C/W 0.001Ω to 100Ω ±0.1% (from 0.001Ω) <30 ppm/°C 10W Non-standard

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