What is Ohm’s Law?

Ohm’s Law is one of the most fundamental principles in electrical engineering and electronics. It describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit.

The Formula:

Where:

• V is the voltage across a component (in volts, V)
• I is the current flowing through it (in amperes, A)
• R is the resistance of the component (in ohms, Ω)

How It Works:

Ohm’s Law tells us that the voltage in a circuit is directly proportional to the current, as long as the resistance remains constant. In simpler terms:

• If you increase the voltage, the current increases (assuming resistance is fixed).
• If you increase the resistance, the current decreases (for the same voltage).
• And if you increase the current, the voltage must also increase (if resistance stays the same).

Example:

Let’s say you have a resistor with a resistance of 10 Ω, and a current of 2 A is flowing through it.
Using Ohm’s Law:

So, the voltage across the resistor is 20 volts.

Why It Matters:

Ohm’s Law is used everywhere — from designing circuits, calculating power requirements, diagnosing electrical faults, to building electronic devices. It lays the foundation for understanding how electrical systems behave.