Ohm's Law Calculator

Calculate voltage, current, resistance, and power using Ohm's Law. Enter any two values to find the others.

Enter any two values to calculate the others

Voltage (V)

Current (A)

Resistance (Ω)

Power (W)

Enter any two values and click Calculate to find the remaining values using Ohm's Law relationships.

Ohm's Law Formulas

V = I × R

Voltage = Current × Resistance

Related Power Formulas:

• P = V × I (Power = Voltage × Current)
• P = I² × R (Power = Current² × Resistance)
• P = V² / R (Power = Voltage² / Resistance)

Units:

• Voltage (V): Volts
• Current (I): Amperes (Amps)
• Resistance (R): Ohms (Ω)
• Power (P): Watts

Example Calculations

LED Circuit Design

Given: 12V supply, LED needs 20mA

Find: Required resistance

Solution: R = V/I = 12V/0.02A = 600Ω

Understanding Ohm's Law

Ohm's Law describes the relationship between voltage, current, and resistance in electrical circuits. It states that the current through a conductor is directly proportional to the voltage across it.

Key Concepts:

• Voltage: The electrical potential difference
• Current: The flow of electrical charge
• Resistance: Opposition to current flow
• Power: Rate of energy consumption

Applications

Electronics Design

Calculate resistor values for LED circuits and voltage dividers

Electrical Safety

Determine safe current levels and power ratings

Energy Efficiency

Calculate power consumption and electrical costs

Circuit Analysis

Analyze and troubleshoot electrical circuits

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