# Ohm’s Law: The Basics

Ohm’s Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them. It can be expressed mathematically as:

I = V / R

Where:

I = current (measured in amperes, A)

V = voltage (measured in volts, V)

R = resistance (measured in ohms, Ω)

For example, consider a simple circuit consisting of a 9V battery and a resistor with a resistance of 3Ω. Using Ohm’s Law, we can calculate the current flowing through the circuit as follows:

I = V / R = 9V / 3Ω = 3A

This means that a current of 3A is flowing through the circuit.

## Calculator

Ohm’s Law Calculator

# Ohm’s Law Calculator

Enter the values for two of the following three quantities: current, voltage, and resistance. The calculator will solve for the third quantity.

Current (I):
Voltage (V):
Resistance (R):

Result:

## FAQ

### What is Ohm’s Law?

Ohm’s Law is a fundamental principle in electrical engineering that describes the relationship between current, voltage, and resistance in an electrical circuit. It states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them.

### How is Ohm’s Law used?

Ohm’s Law is used in a wide range of applications, including the design of electrical circuits, the measurement of electrical quantities, and the analysis of electrical systems. It is a useful tool for predicting the behavior of electrical circuits and for understanding the effects of various circuit components on the overall performance of the circuit.

### What is the equation for Ohm’s Law?

The equation for Ohm’s Law is:

I = V / R

Where:

I = current (measured in amperes, A) V = voltage (measured in volts, V) R = resistance (measured in ohms, Ω)

### How do I use Ohm’s Law to calculate current?

To calculate the current flowing through a conductor using Ohm’s Law, you need to know the voltage across the conductor and the resistance of the conductor. The current can then be calculated using the equation:

I = V / R

For example, if the voltage across a conductor is 12V and the resistance of the conductor is 4Ω, the current flowing through the conductor can be calculated as follows:

I = 12V / 4Ω = 3A

### How do I use Ohm’s Law to calculate resistance?

To calculate the resistance of a conductor using Ohm’s Law, you need to know the current flowing through the conductor and the voltage across the conductor. The resistance can then be calculated using the equation:

R = V / I

For example, if the current flowing through a conductor is 2A and the voltage across the conductor is 6V, the resistance of the conductor can be calculated as follows:

R = 6V / 2A = 3Ω

## Water Pipe Analogy

Ohm’s Law can be explained using an analogy with water flowing through a pipe. In this analogy, the current flowing through a conductor is analogous to the flow rate of water through a pipe, the voltage across the conductor is analogous to the pressure of the water, and the resistance of the conductor is analogous to the diameter of the pipe.

Using this analogy, Ohm’s Law can be stated as follows:

The flow rate of water through a pipe is directly proportional to the pressure of the water and inversely proportional to the diameter of the pipe.

This can be expressed mathematically as:

Flow rate = Pressure / Diameter

This equation is similar to the equation for Ohm’s Law, with the flow rate of water corresponding to the current, the pressure of the water corresponding to the voltage, and the diameter of the pipe corresponding to the resistance.

For example, consider a pipe with a pressure of 10 psi and a diameter of 2 inches. Using the water pipe analogy for Ohm’s Law, we can calculate the flow rate of water through the pipe as follows:

Flow rate = Pressure / Diameter = 10 psi / 2 inches = 5 gallons/minute

This means that a flow rate of 5 gallons per minute is flowing through the pipe.

The water pipe analogy for Ohm’s Law is a useful way to understand the concept of electrical resistance and how it affects the flow of current in an electrical circuit. It can also be used to explain other electrical circuit theorems, such as Kirchhoff’s Current Law and Kirchhoff’s Voltage Law.