When we look back in time, we will encounter a world where electricity was non-existent. Now, in the present, it is almost impossible to live without electricity. Isn’t that quite a leap for a relatively short period in humanity’s history? It is! It just shows how far we’ve integrated electricity into our everyday life.  In this article, let us acquaint ourselves with the necessary electrical theory to understand this useful form of energy better.

## What is an Electric Current?

The flow of electric charges is known as electric current. Based on the direction of the current flow, there are two forms of electric current known as alternating current and direct current.

Direct current (DC) is a unidirectional electric current that flows only in one direction. AC is a current that changes direction periodically along with its voltage polarity. Direct current wrote much of electricity’s history. Alessandro Volta and Thomas Edison were pioneers in DC. But, over time, the long transmission of DC was inefficient. The invention of alternating current overcomes this drawback of DC by Nikola Tesla. Today, power plants produce alternating current while portable devices use DC.

### Electric Circuits

The electric circuits are a closed path of a network of electrical components, where electrons can flow. This path is made using electrical wires and is powered by a source, like a battery. The start of the point from where the electrons start flowing is called the source whereas the point where electrons leave the electrical circuit is called the return.

### Series and Parallel Circuits

The electric circuits can be connected in the form of either a series circuit or a parallel circuit based on the requirement. In series circuits, the electrical components are connected in-line with the power source. The current in a series circuit is constant throughout the circuit, but the voltage may vary. In a parallel circuit, various components branch off from the power supply. The total current supplied from the power source is divided among each of the branches, but voltage is common throughout.

## Fundamental Electrical Laws

### Ohm’s Law

Ohm’s law is a fundamental electrical law that states the relationship between electric current and potential difference. The law states that “the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature remain constant.” Ohm’s law only holds true if the provided temperature and the other physical factors remain constant.

## Kirchhoff’s Law

Kirchhoff’s law is the fundamental law that is used for circuit analysis. Gustav Kirchhoff formulated a pair of laws that deal with the conservation of current and energy within electrical circuits. These two laws are commonly known as Kirchhoff’s Voltage and Current Law. With the help of these laws, we can calculate electrical resistance of a complex network and current flow in different streams of the network. When you amylase electric circuits using Kirchhoff’s laws, you need to be clear with the terminologies and definitions that describe the circuit components such as paths, nodes, meshes, and loops.