Which one of the following statements express the thermal resistance between the body of a power-semiconductor device and the ambient?
- A. Voltage across the device divided by current through the device.
- B. Temperature difference between body and ambient divided by average power dissipated in the device.
- C. Average power dissipated in the device divided by the square of the rms current in the device
- D. Average power dissipated in the device divided by the temperature difference between body and ambient
Answer: B. Temperature difference between body and ambient divided by average power dissipated in the device.
Explanation: Thermal resistance θja = (Tbody - Tambient) / Pavg, defined as temperature difference divided by average dissipated power.