What Is the Resistance and Power for 480V and 1A?

Using Ohm's Law: 480V at 1A means 480 ohms of resistance and 480 watts of power. This is useful for sizing resistors, understanding circuit behavior, and verifying that components can handle the power dissipation (480W in this case).

480V and 1A
480 Ω   |   480 W
Voltage (V)480 V
Current (I)1 A
Resistance (R)480 Ω
Power (P)480 W
480
480

Formulas & Step-by-Step

Resistance

R = V ÷ I

480 ÷ 1 = 480 Ω

Power

P = V × I

480 × 1 = 480 W

Verification (alternative formulas)

P = I² × R

1² × 480 = 1 × 480 = 480 W

P = V² ÷ R

480² ÷ 480 = 230,400 ÷ 480 = 480 W

Circuit Analysis

Heat Dissipation

This circuit dissipates 480 watts of power as heat. In a resistor, all electrical energy at steady state converts to thermal energy. The actual component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve rather than applying a blanket margin.

If You Change the Resistance

ResistanceCurrentPowerChange
240 Ω2 A960 WLower R = more current
360 Ω1.33 A640 WLower R = more current
480 Ω1 A480 WCurrent
720 Ω0.6667 A320 WHigher R = less current
960 Ω0.5 A240 WHigher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 480Ω, here is how current and power scale with source voltage. This is a reference table, not a set of separate circuit scenarios: each row is the same resistor under a different applied voltage.

VoltageCurrent (at 480Ω)Power
5V0.0104 A0.0521 W
12V0.025 A0.3 W
24V0.05 A1.2 W
48V0.1 A4.8 W
120V0.25 A30 W
208V0.4333 A90.13 W
230V0.4792 A110.21 W
240V0.5 A120 W
480V1 A480 W

Frequently Asked Questions

R = V ÷ I = 480 ÷ 1 = 480 ohms.
V=IR, V=P/I, V=√(PR) | I=V/R, I=P/V, I=√(P/R) | R=V/I, R=V²/P, R=P/I² | P=VI, P=I²R, P=V²/R.
For purely resistive loads, yes. For reactive loads, use impedance (Z) instead of resistance (R). Z includes both resistance and reactance, and the V/I phase shift shows up in power factor.
P = V × I = 480 × 1 = 480 watts.
Ohm's Law (V = IR) and the power equation (P = VI) connect all four. Given any two, you can calculate the other two.
This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.