Science & Lab Tools
Ohm's Law Calculator
Calculate voltage, current, resistance, and power in electrical circuits
Enter any two values to calculate the third and power
Related to Ohm's Law Calculator
The Ohm's Law Calculator is based on the fundamental relationship between voltage (V), current (I), and resistance (R) in electrical circuits. This relationship, discovered by Georg Ohm in 1827, states that the current flowing through a conductor is directly proportional to the voltage across the conductor and inversely proportional to its resistance.
Core Formulas
• Ohm's Law: V = I × R (Voltage = Current × Resistance)
• Power Law: P = V × I (Power = Voltage × Current)
• Alternative Power Forms:
- P = I² × R (using current and resistance)
- P = V² ÷ R (using voltage and resistance)
The calculator automatically determines which formula to use based on the values you provide. Enter any two values (voltage, current, or resistance), and the calculator will compute the third value along with the electrical power. All calculations are performed using precise mathematical operations and rounded to three decimal places for practical use.
Understanding the relationships between electrical quantities is crucial for interpreting the results. Here's what each measurement means and how they relate to each other:
Key Measurements
• Voltage (V): The electrical pressure or potential difference measured in volts (V). Higher voltage means more electrical pressure driving the current.
• Current (I): The flow rate of electrical charge measured in amperes (A). Higher current indicates more electrons flowing through the circuit.
• Resistance (R): The opposition to current flow measured in ohms (Ω). Higher resistance means more opposition to current flow.
• Power (P): The rate of electrical energy transfer measured in watts (W). Higher power indicates more energy being transferred per second.
1. What is Ohm's Law used for?
Ohm's Law is used in electrical engineering and electronics to analyze and design circuits. It helps in determining power requirements, selecting appropriate components, troubleshooting electrical problems, and ensuring safe operation of electrical systems.
2. Does Ohm's Law apply to all electrical circuits?
Ohm's Law applies to ideal conductors and many real-world materials, but there are some exceptions. Non-ohmic devices, such as diodes and transistors, don't follow this linear relationship. The law works best for resistive components operating under constant temperature conditions.
3. How accurate are the calculator's results?
The calculator provides results accurate to three decimal places, which is sufficient for most practical applications. However, real-world measurements may vary slightly due to factors like temperature changes, component tolerances, and measurement uncertainties.
4. Can this calculator be used for AC circuits?
This calculator is primarily designed for DC (Direct Current) circuits. For AC (Alternating Current) circuits, additional factors like frequency, inductance, and capacitance need to be considered. The basic principles still apply, but the calculations become more complex.
5. What is the scientific source for this calculator?
This calculator is based on Ohm's Law, a fundamental principle of electrical physics discovered and published by Georg Ohm in "The Galvanic Circuit Investigated Mathematically" (1827). The mathematical relationships have been verified through extensive laboratory experiments and are documented in various physics textbooks and IEEE standards. The power calculations follow the standard electrical power equations derived from Joule's Law of electrical heating. These principles are consistently used in electrical engineering and are verified by organizations like the National Institute of Standards and Technology (NIST) and the International Electrotechnical Commission (IEC).