Ohm's Law Calculator

Fundamental Electrical Calculations

Ohm's Law is a cornerstone of electronics, describing the relationship between voltage, current, and resistance. This powerful calculator extends this principle to include power, allowing you to solve for any one of the four variables if you know any two others.

The Formulas Explained

Ohm's Law and the power formulas form a set of interrelated equations:

• Voltage (V): V = I × R
• Current (I): I = V / R
• Resistance (R): R = V / I
• Power (P): P = V × I, which can also be expressed as P = I² × R or P = V² / R.

How to Use the Calculator

1. Select Value to Calculate: Choose which variable (Voltage, Current, Resistance, or Power) you want to find.
2. Enter Two Known Values: The calculator will display input fields for the other three variables. Fill in any two of them.
3. Calculate: The tool will automatically compute the values of the two missing variables.

Real-World Example

You have a circuit with a 12V power source and a 24Ω resistor. You want to find the current and power.

1. Select 'Current' or 'Power' to calculate.
2. Enter 12 for Voltage (V) and 24 for Resistance (R).
3. The calculator will determine:
   • Current (I): 12V / 24Ω = 0.5 A (Amperes)
   • Power (P): 12V * 0.5A = 6 W (Watts)

Frequently Asked Questions (FAQ)

• What are the units for each variable? Voltage is measured in Volts (V), Current in Amperes (A), Resistance in Ohms (Ω), and Power in Watts (W).
• Why does the calculator need two values? Because the four variables are interrelated, providing any two known values allows for the algebraic solution of the other two.
• What happens if I try to divide by zero? If you enter a resistance of 0 while trying to calculate current (I = V/R), the calculator will indicate an error, as this represents a short circuit with theoretically infinite current.