 Electric Current

An electric current is an ordered (directed) movement of charged particles under the influence of an electric field.

These particles are different in different substances. For example, in metals, these are electrons. But in gases, these are ions and electrons. In a solution of acids and salts (electrolytes), these are positive ions (cations) and negative ions (anions). For semiconductors, these are electrons and holes.

Sometimes the definition becomes different. For example, not the movement of charged particles, but transferring an electric charge from one particle to another. There is another opinion. Electrons move in the opposite direction to the current. So electric current is not the movement of particles.

In higher education institutions this definition is no longer found. There, the current is more likely to be called the rate of change of the electric charge over time.

## Definition of Electric current

William Gilbert (1544 - 1603) - an English physicist. He gave the following definition of this phenomenon:

"Electricity is a set of phenomena caused by the existence, interaction, and movement of electric charges".

"Electrical Current is an electric charge that flows through the conductor in each unit of time. Electric charge produces by electrons and protons inside an atom".

Protons have a positive charge, while electrons have a negative charge. However, most Protons only move inside the nucleus.

So, electrons handle the movement of a charge from one place to another.

So, the electrons in a conductor can swing from one atom to another.

Atoms in a conductor have many electrons that move from one atom to another in random directions, so they do not flow in one particular direction.

But when a voltage is applied to the conductor, all free electrons will move in the same direction, creating an electrical current.

### Easy Formula

We usually denoted electric current by the letter "I" which means "intensity (intensity)".

While the Electrical Current unit is Ampere, which is usually abbreviated with the letter "A" or "Amp".

The amperage of electrical current can be defined as the number of electrons or charges (Q or Coulombs) that pass a certain point in 1 second (I = Q / t).

Whereas in Ohm's Law states that the amount of Electrical Current (I) that flows through a conductor or conductor is directly proportional to the potential difference or voltage (V) and inversely proportional to the resistance (R). Ohm's Law Formula is I = V / R.

We can analogize electrical current as of the flow of water in a water tank. The greater the water pressure and the smaller the resistance in the pipe, the amount of water flow will also be large.

Likewise, the flow of electrical current, the higher the applied voltage, and the smaller the electrical resistance in a circuit, the greater the electric current.

### Electric Current Flow

In the theory of electric current flow, we know that there are two theories about the flow of electric current that are the flow of conventional electric current (conventional current flow) and electron flow (electron flow).

#### Conventional Electric Flow

Conventionally we often mention that the flow of electricity in an electronic circuit is flowing from the positive (+) direction to the negative (-) direction. The direction of conventional current flow is the flow of current using the principle of charge, where electric current is often defined as the flow of positive electric charges at a conduit from high potential to low potential. But the direction of the flow of electric current is contrary to the principle of the flow of electrons in a conductor.

The concept of a circuit with the conventional electric current flow is used to understand the direction of the flow of electric charge from positive to negative.

#### Electron Flow

The direction of the flow of electrons is opposite to the direction of the flow of conventional electric current.

Because electrons are negatively charged and freely moving particles drawn to the positive terminal.

Thus, the direction of electric current in a circuit is the flow of electrons from the negative pole of the battery (cathode) to the positive pole of the battery (anode).

So the electron flow from the negative direction (-) to the positive direction (+).

### Definition of DC Electric Current and AC Electric Current

There are two types of electric current based on the direction of the flow of electricity.

Electric current flowing in one direction or in the same direction is called Direct Current or in English is called Direct Current, abbreviated as DC.

Examples of direct current sources are batteries, solar cells, and power supplies.

While when electric current flows in the direction that always changing is called alternating Current, abbreviated as AC.

AC waveforms are Sinus waves. But in certain applications, there are also triangular waveforms and square waveforms.

Examples of alternating current are PLN electricity, and electricity generated by electric generators.