Enter any two values below to calculate the third using V = I × R
What is Ohm’s Law?
Ohm’s Law is a fundamental principle in electronics and physics, stating the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit:
V = I × R — Voltage equals current multiplied by resistance.
- Voltage (V) is the electrical potential difference (measured in volts).
- Current (I) is the flow of electric charge (measured in amperes).
- Resistance (R) is the opposition to current flow (measured in ohms).
Real-World Example
Suppose you have a 12V battery connected to a resistor, and you want to limit the current to 2 amps to protect your LED strip. Using Ohm’s Law:
R = V / I = 12 / 2 = 6Ω
So, you’ll need a 6-ohm resistor.