Ohm’s Law

Key Notes:

Ohm’s Law

  1. Definition: Ohm’s Law is a fundamental principle in electricity and electronics that relates the three main electrical quantities: voltage (V), current (I), and resistance (R).
  2. Mathematical Representation: Ohm’s Law is expressed as a simple equation:
Ohm's Law Equation
   V = I * R

Where:

  • V represents voltage in volts (V).
  • I represents current in amperes (A).
  • R represents resistance in ohms (Ω).
  1. Relationship: Ohm’s Law states that the voltage across a resistor is directly proportional to the current passing through it, while inversely proportional to the resistance of the resistor.
  2. Graphical Representation: The relationship can also be depicted graphically as a straight line on a V-I graph, where the slope of the line represents the resistance.
  3. Unit of Resistance: The unit of resistance is the ohm (Ω).
  4. Practical Applications:
  • Ohm’s Law is crucial in designing and analyzing electrical circuits.
Ohm’s Law Statement: Ohm’s law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant.Ohm’s Law Equation: V = IR, where V is the voltage across the conductor, I is the current flowing through the conductor and R is the resistance provided by the conductor to the flow of current.
  • It helps in determining the voltage, current, and resistance values in various components of a circuit.
  1. Example: If a resistor has a resistance of 10 ohms (R = 10 Ω) and a current of 2 amperes (I = 2 A) flows through it, the voltage across the resistor can be calculated using Ohm’s Law:
Ohm's Law Equation
   V = I * R
   V = 2 A * 10 Ω = 20 V

So, the voltage across the resistor is 20 volts.

  1. Series and Parallel Circuits: Ohm’s Law can be used to analyze series and parallel circuits, helping to find total resistance, total current, and individual component values within the circuit.
  2. Limitations: Ohm’s Law is most accurate for linear, passive components like resistors. It may not apply to non-linear devices like diodes and transistors.
  3. Summary: Ohm’s Law is a fundamental tool for understanding and working with electrical circuits, allowing engineers and technicians to calculate and predict how voltage, current, and resistance interact within a circuit.

Understanding Ohm’s Law is essential for anyone studying or working with electricity and electronics, as it forms the basis for many aspects of electrical engineering and circuit design.

Let’s practice!