Ohm's Law Calculator
Calculate voltage, current, resistance, and power in electrical circuits using Ohm's Law. Enter any two known values and the calculator will solve for the other two.
Calculation Results
| Parameter | Value |
|---|---|
| Voltage (V) | - |
| Current (I) | - |
| Resistance (R) | - |
| Power (P) | - |
Ohm's Law Formulas
| To Find | Formula |
|---|---|
| Voltage (V) | V = I × R |
| Current (I) | I = V ÷ R |
| Resistance (R) | R = V ÷ I |
| Power (P) | P = V × I |
| Power (P) from I & R | P = I² × R |
| Power (P) from V & R | P = V² ÷ R |
About Ohm's Law Calculator
Our Ohm's Law calculator is a comprehensive tool designed to help you solve electrical circuit problems by calculating voltage, current, resistance, and power. Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
How to Use the Calculator
- Enter any two known values (voltage, current, resistance, or power) in their respective fields.
- Select the appropriate units for each value (V, A, Ω, W or their multiples).
- Click the "Calculate" button to compute the unknown values.
- The results will be displayed in the results table and visualized in the chart.
- Use the "Clear" button to reset all fields and start a new calculation.
Understanding Ohm's Law
Ohm's Law is a fundamental principle in electrical engineering and physics that describes the relationship between voltage, current, and resistance in an electrical circuit. The law is named after the German physicist Georg Ohm, who first formulated it in 1827.
The mathematical expression of Ohm's Law is:
V = I × R
Where:
- V is the voltage across the conductor (in volts)
- I is the current through the conductor (in amperes)
- R is the resistance of the conductor (in ohms)
Power Calculations
Electrical power is the rate at which electrical energy is transferred by an electric circuit. The basic formula for power is:
P = V × I
Where:
- P is the power (in watts)
- V is the voltage (in volts)
- I is the current (in amperes)
Using Ohm's Law, we can derive two additional power formulas:
P = I² × R (Power equals current squared times resistance)
P = V² ÷ R (Power equals voltage squared divided by resistance)
Practical Applications
Ohm's Law is used in various electrical and electronic applications:
- Determining the appropriate resistor value for LEDs
- Calculating current draw in circuits
- Sizing wires and fuses for electrical installations
- Designing voltage dividers
- Troubleshooting electrical circuits
- Calculating power consumption of devices
Units and Multiples
Electrical quantities can be expressed in different units depending on their magnitude:
| Quantity | Base Unit | Common Multiples |
|---|---|---|
| Voltage | Volt (V) | millivolt (mV), kilovolt (kV) |
| Current | Ampere (A) | milliampere (mA), microampere (μA) |
| Resistance | Ohm (Ω) | kilohm (kΩ), megohm (MΩ) |
| Power | Watt (W) | milliwatt (mW), kilowatt (kW) |