Electronics
Ohm's law
The core relationship. Rearrange to I = V / R for current or R = V / I for resistance; all three are the same equation.
The Formula
V = I x R
The core relationship. Rearrange to I = V / R for current or R = V / I for resistance; all three are the same equation.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| V | Potential difference across the component | volts | The electrical push that drives charge around the circuit. |
| I | Current through the component | amperes | Same value everywhere in a series path; splits across parallel branches. |
| R | Resistance of the component | ohms | Constant only for a linear component. Must never be zero in this form. |
What Each Symbol Means
Vvolts
Potential difference across the component
The electrical push that drives charge around the circuit.
Iamperes
Current through the component
Same value everywhere in a series path; splits across parallel branches.
Rohms
Resistance of the component
Constant only for a linear component. Must never be zero in this form.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate ohm's law page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Ohm's Law, filed under Science. Every number the guide produces comes from substituting into this one line.