What is current in electricity?

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What is current in electricity
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Let me make you understand what the current is in electricity.

Table of Contents

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What is current?

Voltage exerts force on free electrons to move. Current is movement of free electrons through a conductor

Why the unit of Current is Ampere?

Now, this is quite interesting to know.

The ampere was named after André Ampère, a scientist who lived in the late 1700s and early 1800s.

Ampère is well known for his work on electromagnetic.

The number of electrons passing through a cross-section of a conductor in one second determines the amount of current flowing.

One coulomb in one second

It is important to note that the definition of an ampere includes both a quantity measurement, the coulomb, and a time measurement, the second.

Due to the very small size of atoms, it takes about 1024 electrons to fill one cubic centimeter of a copper conductor.

The ampere is a unit of measurement for the quantity of electricity passing through a circuit.

It is analogous to gallons per minute or gallons per second in a water system shown in below figure.

Current comparison with flow rate in water system

In algebraic formulas, the letter I, which represents for current intensity, and the letter A, which stands for ampere, are both used to denote current flow.  

The direction of the Current flow

The direction of the current flowing has two different theories:

  • Conventional Flow theory
  • Electron Flow theory

Conventional Flow

This theory states that electrons flow from positive to negative.

Benjamin Franklin theorized this when very little was known about electricity.

It states that an invisible fluid known as electricity tended to flow through a wire from the positive to the negative.

Ben’s theory became the convention (hence the term “conventional current”) in electrical theory, mathematics, textbooks, and electrical equipment for the next hundred years.

The negative terminal is used as ground or common in most electrical circuits.

When the negative terminal is utilized as ground, the positive terminal is seen as being above ground, or hot.

Most people prefer to imagine something flowing down rather than up, or from a point above ground to ground.

A good example of this type of circuit is the electric system in a car. Most people believe that the positive battery terminal is the hot terminal.

Because all of the arrows on semiconductor symbols point in the direction of conventional current flow, many individuals in the electronics profession favor it.

If the electron flow hypothesis is utilized, it must be assumed that current flows in the opposite direction of the arrow.

Conventional Current Flow

Another reason why many people prefer traditional current flow theory is because most electrical schematics are drawn in such a way that current flows from more positive to more negative sources. The positive voltage point is indicated at the top of the schematic, while the negative (ground) point is shown at the bottom.

Most individuals prefer to trace the flow of current through a circuit from top to bottom rather than bottom to top.

Electron Flow

This theory states that electrons flow from negative to positive. More research carried out on the behavior of electrons.

Scientists discovered that electrons actually flow from negative to positive. Since electrons are negatively charged, it is attracted towards positively charged bodies and repelled by negatively charged bodies.

Electron flow

 

Understanding Current with a Water Tank analogy

Imagine a water tank over the roof of a residential house. Water flows from the tank to the tap through the pipe. In a similar manner, in an electric circuit, due to the force of voltage, free electrons inside the conductor starts moving. So current is nothing but the movement of electrons flowing through the conductor.

Water Tank analogy for Current

Summarizing current

We can say in short that, the current is ‘flow of electrons’ in an electric circuit.

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Next articleWhich is more dangerous AC or DC current?
Krunal Shah is Electrical and Electronics Engineer with almost 12 years of experience in corporate in relevant field before starting Engineers Hub. He loves to share his experience and knowledge and that makes him a passionate educator and career-counselor also. Along with Engineers Hub he also runs Subodh Tech Private Limited where he is involved in providing job-oriented training and Engineering Consultancy.

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