Resistor Power Dissipation (I²R)
Resistor Power Dissipation (I²R)
A resistor carrying current dissipates power as heat at a rate set by the current squared times resistance — the I²R loss.
The power is P = I²·R. where I is the current and R the resistance.
Inputs
I := 2.5 A=2.5 A
R := 12 Ohm=12 Ω
Apply the I²R power formula.
P := I^2·R=75 W
Results
Because it scales with the square of current, doubling the current quadruples the heat. This sets resistor wattage ratings and cable heating.
Assumptions & limitations
- DC or RMS current.
- Constant resistance.
- Steady state.