Formula
Ohm's law for the current through a resistor is:
Amperes = volts / ohms
A zero resistance is rejected. The wattage page uses current as an input instead of finding it.
Assumptions
- The component follows Ohm's law.
- Resistance is greater than zero.
Worked example
12 V across 4 Ω is 3 A.
Input definitions
- Voltage
- The potential difference, in volts.
- Resistance
- The resistance, in ohms.
Limitations
This is a classroom calculation. It is not a laboratory procedure, a wiring plan, or a measured instrument reading.
Questions
Why is resistance not allowed to be zero?
Dividing by zero is not a current. A short circuit is outside this formula.
Is this the same as the Ohm's law page?
That page can solve for any one unknown. This page only solves for current.