A Beginner's Guide to Ohm's Law

Ohm's Law is the foundation of electronics. It describes the relationship between the three most basic electrical concepts: Voltage, Current, and Resistance.

1. The Core Components

Voltage (V): Measured in Volts. Think of this as "water pressure" pushing electricity through a wire.
Current (I): Measured in Amps. This is the actual flow rate of the electricity.
Resistance (R): Measured in Ohms (Ω). This is how much the material resists the flow of electricity.

The Magic Triangle Formula:
V = I × R
I = V / R
R = V / I

2. How to use it

If you know any two of these values, you can find the third. For example, if you have a 9V battery and a lightbulb with a resistance of 100Ω, you can calculate the current (I) by dividing 9 by 100 (0.09 Amps).

3. What about Power (W)?

Power, measured in Watts, is the rate at which energy is used. It is calculated by multiplying the Voltage by the Current (P = V × I).

← Back to Ohm's Law Calculator