# What is Electric Current? | Definition, Types, Formula & Examples

## What is Electric Current?

Electric current is the flow of an electric charge. It is an important quantity in electronic circuits. Current flows in a circuit when a potential difference is applied between two points of a conductor.

## Flow of Electrons

In an electronic circuit, current is the flow of electrons. However, normally the current is specified in the direction of the positive charges. In fact, it is in the opposite direction of the motion of the electrons in the circuit.

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## How is Current measured?

The standard unit for measuring amperage is the ampere. It is sometimes abbreviated as A or Amps. The symbol used for electric current is the letter “i”.

Current is measured as the flow of charge over time through a certain point in an electrical circuit. One ampere equals 1 coulomb for 1 second. A coulomb is a standard unit of electric charge.

## Calculating Current

The current can be calculated using Ohm’s law. It can also be used to determine the resistance of a circuit if the voltage is known, or the voltage of the circuit if the resistance is known.

I = V/R

where I = current, V = voltage, and R = resistance

Current is also used to calculate power according to the following equation:

P = I * V

where P = power, I = current, and V = voltage.

## AC versus DC

There are two main types of current used in most electronic circuits today. These are alternating current (AC) and direct current (DC).

**Direct Current (DC) –** Direct current is the constant flow of electric charge in one direction. Batteries generate direct current to power portable devices. Most electronic devices use direct current for internal power, usually converting alternating current (AC) to direct current (DC) using a transformer.

**Alternating Current (AC) –** Alternating current is an electric current in which the flow of electric charge continuously changes direction. Alternating current is mainly used today to transmit power through power lines. In the United States, the frequency of alternating current is 60 Hertz. Some other countries use 50 Hertz as the standard frequency.

## Electromagnetism

Electric current also plays an important role in electromagnetism. AmpĂ¨re’s law describes how a magnetic field is created by an electric current. This technology is used in electric motors.

## Interesting Facts about Current

The direction of the current is usually indicated by an arrow. In most electronic circuits, current is represented as flowing to ground.

The current in the circuit is measured with an instrument called an ammeter.

Sometimes the current flowing through a wire can be thought of as the same as passing water through a pipe.

Conductivity of a material is a measure of its ability to conduct electric current.