Power Dissipation from Temperature Rise
Infer steady-state power dissipation as (Tj−Ta)/θJA from a measured junction and ambient temperature. Use the effective thermal resistance for the same assembly and cooling conditions.
Description
Infer steady-state power dissipation as (Tj−Ta)/θJA from a measured junction and ambient temperature. Use the effective thermal resistance for the same assembly and cooling conditions.
Power Dissipation from Temperature Rise: Infer steady-state power dissipation as (Tj−Ta)/θJA from a measured junction and ambient temperature. Use the effective thermal resistance for the same assembly and cooling conditions.
When to use Power Dissipation from Temperature Rise
Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.
- Junction temperature (°C)
- Required number input.
- Ambient temperature (°C)
- Required number input.
- Junction-to-ambient resistance (°C/W)
- Required number input.
How Power Dissipation from Temperature Rise works
Infer steady-state power dissipation as (Tj−Ta)/θJA from a measured junction and ambient temperature. Use the effective thermal resistance for the same assembly and cooling conditions. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.1
- Power W
- The resulting power w returned as a number.
Limitations and assumptions
- Thermal-resistance arithmetic assumes the stated heat path, steady state, reference temperatures, and approximately linear properties. Interface materials, airflow, orientation, spreading resistance, transient thermal impedance, nearby heat sources, mounting torque, and enclosure temperature can dominate junction temperature.
- Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.
Alternative or Complementary approaches
Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.
References
-
Thermal conductance and resistance — Wikipedia contributors
Similar or alternative tools
- Junction-to-Ambient Thermal Resistance
Infer effective junction-to-ambient thermal resistance as (Tj−Ta)/P for a steady operating point. The value depends on board and airflow conditions and is not necessarily the datasheet test value.
- Thermal Resistance °C/W
Derive the junction-to-ambient thermal resistance from a steady-state temperature rise over dissipated power.
- Transformer Temperature Rise Estimate
Estimate steady transformer temperature rise as total heat dissipation multiplied by measured effective thermal resistance to ambient. Airflow, enclosure, mounting, and temperature-dependent losses can change the actual rise.