Variable Solver Calculator

Ohm's Law Calculator

Use this calculator to solve for Voltage (V), Current (I), or Resistance (R) using Ohm's Law (V = I × R). Enter any two values, and the calculator will determine the third.

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Understanding Ohm's Law and Its Applications

Ohm's Law is a fundamental principle in electrical engineering and physics, describing the relationship between voltage, current, and resistance in an electrical circuit. Named after German physicist Georg Simon Ohm, this law is crucial for understanding how electricity flows and for designing electronic components and systems.

The Formula: V = I × R

At its core, Ohm's Law is expressed by the simple equation:

V = I × R

Where:

• V stands for Voltage, measured in Volts (V). Voltage is the electrical potential difference between two points, representing the "push" or force that drives electric current.
• I stands for Current, measured in Amperes (A). Current is the rate of flow of electric charge through a conductor.
• R stands for Resistance, measured in Ohms (Ω). Resistance is the opposition to the flow of electric current.

How the Ohm's Law Calculator Works

Our Ohm's Law Calculator simplifies the process of solving for any of these three variables when the other two are known. You simply input the values for two of the variables (Voltage, Current, or Resistance), leave the third one blank, and the calculator will automatically determine the missing value based on the following derivations of Ohm's Law:

• To find Voltage (V): If you know Current (I) and Resistance (R), the formula is V = I × R.
• To find Current (I): If you know Voltage (V) and Resistance (R), the formula is I = V / R.
• To find Resistance (R): If you know Voltage (V) and Current (I), the formula is R = V / I.

Practical Examples

Let's look at some real-world scenarios where this calculator can be incredibly useful:

Example 1: Calculating Voltage

Imagine you have a circuit with a current of 2 Amperes (A) flowing through a resistor with a resistance of 6 Ohms (Ω). What is the voltage across the resistor?

• Enter Current (A): 2
• Enter Resistance (Ω): 6
• Leave Voltage (V) blank.

The calculator will output: Voltage: 12.0000 Volts (V) (since V = 2A × 6Ω = 12V).

Example 2: Calculating Current

Suppose a 12-Volt (V) car battery is connected to a headlight with a resistance of 4 Ohms (Ω). How much current flows through the headlight?

• Enter Voltage (V): 12
• Enter Resistance (Ω): 4
• Leave Current (A) blank.

The calculator will output: Current: 3.0000 Amperes (A) (since I = 12V / 4Ω = 3A).

Example 3: Calculating Resistance

If a small LED light draws 0.02 Amperes (A) of current when connected to a 3-Volt (V) power source, what is the resistance of the LED?

• Enter Voltage (V): 3
• Enter Current (A): 0.02
• Leave Resistance (Ω) blank.

The calculator will output: Resistance: 150.0000 Ohms (Ω) (since R = 3V / 0.02A = 150Ω).

Importance of Ohm's Law

Ohm's Law is fundamental for:

• Circuit Design: Engineers use it to determine appropriate resistor values, power supply requirements, and current limits for various components.
• Troubleshooting: Technicians can diagnose circuit problems by measuring two variables and calculating the third to see if it matches expected values.
• Safety: Understanding the relationship between voltage, current, and resistance helps in preventing overcurrents that can damage equipment or cause hazards.

Whether you're a student learning about electricity, an electronics hobbyist, or a professional engineer, this Ohm's Law calculator is a handy tool for quick and accurate calculations.

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