# Ohm’s law

## Introduction to Ohm’s Law

Ohm’s Law is a fundamental concept in the field of electrical engineering. It is named after the German physicist Georg Simon Ohm, who first introduced it in 1827. Ohm’s Law describes the relationship between current, voltage, and resistance in an electrical circuit. This law can be used to calculate the amount of current that flows through a circuit, given the voltage and resistance, or to calculate the voltage required to produce a specific amount of current.

Ohm’s Law is based on the principle that the current flowing through a circuit is directly proportional to the voltage applied across the circuit and inversely proportional to the resistance of the circuit. This relationship is expressed mathematically as:

I = V/R

Where I is the current in amperes, V is the voltage in volts, and R is the resistance in ohms.

## Understanding the Variables in Ohm’s Law

To understand Ohm’s Law, it is important to understand the three variables involved: current, voltage, and resistance.

• Current (I): Current is the flow of electric charge through a circuit. It is measured in amperes (A). The greater the current, the more charge is flowing through the circuit.
• Voltage (V): Voltage is the electrical potential difference between two points in a circuit. It is measured in volts (V). The greater the voltage, the more energy is available to move charge through the circuit.
• Resistance (R): Resistance is the measure of how much a material opposes the flow of electric current. It is measured in ohms (Ω). The greater the resistance, the more difficult it is for current to flow through the circuit.

## How to Apply Ohm’s Law in Circuits

Ohm’s Law can be used to calculate the current flowing through a circuit, given the voltage and resistance, or to calculate the voltage required to produce a specific amount of current. The formula for Ohm’s Law is:

V = IR

Where V is the voltage in volts, I is the current in amperes, and R is the resistance in ohms.

To apply Ohm’s Law in a circuit, you need to know at least two of the variables: voltage, current, or resistance. Once you know two of the variables, you can use the formula to calculate the third variable.

## Example Problems Using Ohm’s Law

1. What is the current flowing through a circuit with a resistance of 10 ohms and a voltage of 20 volts?
I = V/R
I = 20V / 10Ω
I = 2A

The current flowing through the circuit is 2 amperes.

1. What voltage is required to produce a current of 5 amperes through a circuit with a resistance of 20 ohms?
V = IR
V = 5A x 20Ω
V = 100V

A voltage of 100 volts is required to produce a current of 5 amperes through the circuit.

Ohm’s Law is a powerful tool that can be used to understand and analyze electrical circuits. By understanding the relationship between current, voltage, and resistance, you can design and troubleshoot circuits with greater efficiency and accuracy.