# Thermal effect calculator

## This calculator and equation help determine the junction temperature of the heat sink. Most commonly used with power devices, calculating the junction temperature of a device works around four criteria: the ambient temperature, the device’s thermal resistance, the thermal resistance of the heat sink and the power applied to the device.

Inputs
Material
Weight
Temperature Rise
Degrees Celsius or Kelvin
Energy
Joules

Output

TJ  = Junction temperature

Ta = Ambient temperature

P = Power dissipated

Rcase = Thermal resistance of device junction to case

R1 = Thermal resistance of heat sink

R2 = Thermal resistance of device junction to air

### Equations

$$TJ = P(Rcase + R1 + R2) + Ta$$