Ohm’s Law Calculator
Calculate voltage, current, resistance, and power using fundamental electrical principles
Ohm’s Law Formulas
Enter any two values to calculate the other two. Ohm’s Law defines the relationship between voltage (V), current (I), and resistance (R):
Voltage Formula
V = I × R
Current Formula
I = V ÷ R
Resistance Formula
R = V ÷ I
Power Formula
P = V × I
Voltage
Current
Resistance
Power
Understanding Ohm’s Law
What is Ohm’s Law?
Ohm’s Law is a fundamental principle in electrical engineering that defines the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. Formulated by German physicist Georg Ohm in 1827, it states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.
The Mathematical Formula
The standard mathematical representation of Ohm’s Law is:
V = I × R
Where:
- V is voltage in volts (V)
- I is current in amperes (A)
- R is resistance in ohms (Ω)
Power Calculations
Electrical power (P) in watts is calculated using:
P = V × I
This can also be expressed in terms of resistance:
P = I² × R or P = V² ÷ R
Practical Applications
Ohm’s Law is essential for designing and analyzing electrical circuits. It helps in:
- Determining appropriate resistor values for circuits
- Calculating power consumption of electrical devices
- Troubleshooting electrical problems
- Designing safe electrical systems with proper wire gauges
- Understanding the relationship between electrical components