How it is calculated
For direct current and a plain resistance. Reactive power on alternating current is not separated out here.
U = I × R, P = U × I
Where the numbers come from
- Voltage — unit in the field: V
- Current — unit in the field: A
- Resistance — unit in the field: Ω
Example
12 V and 2 A give 6 Ω and 24 W.
Questions
Does an empty field mean zero?
No. An empty field is what the calculator solves for. Type zero in explicitly, but it will refuse to divide by zero.
Milliamps?
Convert to amperes: 500 mA = 0,5 A.
All three fields are filled and do not agree?
A third quantity that is already filled in is not recalculated. Resistance on the screen stays as you typed it, and power is U×I.