Ohm’s Law: The Foundation of Electrical Circuits

Introduction

Ohm’s Law defines the relationship between voltage (V), current (I), and resistance (R). It is crucial for anyone working with electronics and electrical circuits.

Ohm’s Law Formula

The fundamental equation of Ohm’s Law is:

V = I × R

Ohm’s Law Triangle

• To find Voltage (V): V = I × R
• To find Current (I): I = V / R
• To find Resistance (R): R = V / I

Ohm’s Law Examples

Voltage Calculation

• Example 1: If I = 2A and R = 5Ω, then V = 2 × 5 = 10V.
• Example 2: If I = 0.5A and R = 20Ω, then V = 0.5 × 20 = 10V.
• Example 3: If I = 4A and R = 6Ω, then V = 4 × 6 = 24V.

Current Calculation

• Example 4: If V = 12V and R = 6Ω, then I = 12 / 6 = 2A.
• Example 5: If V = 24V and R = 8Ω, then I = 24 / 8 = 3A.
• Example 6: If V = 9V and R = 3Ω, then I = 9 / 3 = 3A.

Resistance Calculation

• Example 7: If V = 15V and I = 3A, then R = 15 / 3 = 5Ω.
• Example 8: If V = 120V and I = 10A, then R = 120 / 10 = 12Ω.
• Example 9: If V = 30V and I = 2A, then R = 30 / 2 = 15Ω.
• Example 10: If V = 5V and I = 0.25A, then R = 5 / 0.25 = 20Ω.

Ohm’s Law Circuit Diagram

Where:

• V = Voltage source (Battery)
• R = Resistor
• I = Current flow

Ohm’s Law Calculations examples with circuit diagrams

Q1:

Given: V = 5V, R = 400Ω
Find: I?

Using Ohm’s Law:

I = V / R

I = 5V / 400Ω = 0.0125A or 12.5mA

Q2:

Given: I = 12.5mA, R = 400Ω
Find: V?

Using Ohm’s Law:

V = I × R

V = 0.0125A × 400Ω = 5V

Q3:

Given: V = 5V, I = 12.5mA
Find: R?

Using Ohm’s Law:

R = V / I

R = 5V / 0.0125A = 400Ω

Real-World Applications

• LED Circuits: Choosing correct resistors to prevent LED damage.
• Battery Sizing: Ensuring enough power supply for devices.
• Automotive Electronics: Designing circuits in vehicles.

Try Our Ohm’s Law Calculator! 🧮

Use our Ohm’s Law Calculator to quickly determine voltage, current, or resistance.

Use the Calculator Now

Conclusion

Ohm’s Law is a fundamental principle in Electrical and electronics, making circuit design and troubleshooting easier. Mastering this concept allows you to build efficient and reliable electrical systems.