Electrical Quantities

Basic Electrical Quantities

Today’s electronics are based on a number of basic concepts that we use every day. Electronics is the study of the flow of current through an electric circuit. There are two categories in which electronics are divided, and they are a communication system and a control system. Both systems are based on basic electrical quantities. Through this article, we will get introduced to a number of definitions of various electrical quantities and their units. 

Electrical Quantities

There are six basic electrical quantities, and they are as follows:

  • Voltage 
  • Current 
  • Power 
  • Resistance 
  • Capacitance 
  • Inductance 

The main objective of this article is to understand a few basic terminologies in electronics. It includes electricity, voltage definition, defining current, resistance, understanding the SI units of power, resistance, and inductance.


What is Voltage?

Voltage is defined as the pressure experienced by the electrons in a current-carrying conductor which is responsible for their flow in the electrical circuit. When the positive potential is placed on one end of the conductor, it attracts the negative charges. This takes place due to the fact that charges are attractive in nature. As the potential of attraction increases, the flow of electrons increases.

Voltage is measured in terms of a volt. It is the basic unit of measurement which is named after the Italian scientist Alessandro Volta. 


Volt is defined as the difference between the electric potential between two points of a conductor carrying one ampere of current has a power dissipation which is equal to one watt.


What is Power?

The power which is also known as electric power is defined as the rate of electrical energy that is transferred in an electric circuit per unit time. 


The unit of power is watt which is denoted as “W”. This is named after the Scottish engineer James Watt and is defined as the rate at which work is done when one ampere current flows through the circuit with an electric potential difference of one volt.


What is Resistance?

Resistance is defined as the hindrance experienced by the flow of charges. As the voltage increases, the resistance decreases. Also, voltage and resistance are the two parameters on which the flow of charges is dependent.


The following are the factors on which the resistance of a material are dependent:

  • The structure of the conductor.
  • The length of the material.
  • The cross-sectional area of the material.

Considering the above three factors, copper is selected as the best conductor as the structure of the copper allows more flow of charges. Also, the cross-sectional area is wide enough to carry the charges.


What is Current?

Now let us see how we can define the current. The flow of electric charges in a circuit is the current definition. It is the rate of flow of charges across a point in an electric circuit. These charges are positive charges which include protons or holes and negative charges which include electrons.


Current is measured in ampere and is denoted by “A”. The magnitude of the current is measured in Coulombs per second. According to Ohm’s law, the relationship between voltage, current, and resistance is given as:

V = IR

That is voltage is the product of the electric current and its resistance.

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