Ohm's law

Ohm's law describes the mathematical relationship between electrical voltage, current, and resistance in a conductor.

Key Concepts

1. Voltage ($V$)

   • Measured in volts ($\text{V}$).

   • Represents the potential difference or electrical force pushing charges through a circuit.

2. Current ($I$)

   • Measured in amperes ($\text{A}$).

   • Represents the rate of flow of electric charge through the conductor.

3. Resistance ($R$)

   • Measured in ohms ($\Omega$).

   • Represents the opposition to the flow of electric current.

Mathematical Formula

Ohm's law states that the current passing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance:

$V = I R$

The formula can be rearranged to determine any of the three parameters:

• Current: $I = \frac{V}{R}$

• Resistance: $R = \frac{V}{I}$

Limitations

• Ohmic Materials: Metals and standard resistors follow Ohm's law under constant temperature conditions.

• Non-Ohmic Materials: Devices such as diodes, LEDs, and filament bulbs do not follow Ohm's law, as their resistance changes with voltage or current.