Basic Electrical Theory: Questions and Answers

Electrical theory may seem daunting, but with a clear breakdown of its core principles, it becomes accessible. This article presents fundamental questions and their straightforward answers, guiding readers through the basics of electricity and its application.

The world of electrical theory can seem complex, but when broken down into its fundamental concepts, it’s a subject that anyone can begin to understand. In this article, we will address several basic questions about electrical theory, providing straightforward answers to help you grasp these foundational concepts.


1. What is electrical theory?

Electrical theory is a body of principles that explain how electricity works. It describes the behavior of electric charge, its interactions, and how we can use it to perform work. Electrical theory covers concepts such as voltage, current, resistance, power and the relationships between them, providing the foundational knowledge needed to understand, create, and repair electrical systems.

2. What is electric charge?

Electric charge is a fundamental property of matter. Furthermore, there are two types of electric charges: positive and negative. Like charges repel each other, while opposite charges attract. The movement or flow of electric charges constitutes an electric current.

3. What is electric current?

Electric current is the rate at which electric charge flows through a conductor, such as a wire. We usually measure it in amperes (A), also known simply as amps. The direction positive charges would move defines the direction of the current. In metals, negatively charged electrons are the actual charge carriers, moving in the opposite direction of the current.

4. What is voltage?

Voltage, also known as electric potential difference, is the force that pushes electric charge around a circuit. It’s the ‘pressure’ behind the flow of electricity, often compared to water pressure in a pipe. Voltage measures in volts (V).

5. What is resistance?

Resistance is a measure of the opposition to the flow of electric current. It describes how a material or an electronic component resists or obstructs the flow of electric charge. Resistance measures in ohms (Ω).

6. What is Ohm’s Law?

Ohm’s Law is a fundamental principle of electrical theory that describes the relationship between current, voltage, and resistance. It states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to the resistance. It can be written as I = V/R, where I is current, V is voltage, and R is resistance.

7. What are Kirchhoff’s Laws?

Kirchhoff’s Laws are two principles vital for analyzing electrical circuits.

In Kirchhoff’s Current Law (KCL) it states that the total current entering a node or a junction in a circuit is equal to the total current leaving that node.

Kirchhoff’s Voltage Law (KVL) states that the sum of electrical potential differences (voltages) around any closed loop or path in a circuit is zero. In other words, the voltages generated by sources around a loop must equal the sum of the voltage drops across all elements around the same loop.

8. What is the difference between AC and DC?

AC stands for Alternating Current, where the flow of electric charge periodically reverses direction. DC stands for Direct Current, where the flow of electric charge is in one constant direction. Household outlets provide AC, while batteries typically supply DC.

9. What is power in an electrical circuit?

In the context of electrical theory, power is the rate at which electrical energy is transferred or converted. Additionally, it can be calculated as the product of voltage and current (P=IV), and is typically measured in watts (W).

Struggling with electrical circuit theory? Check out our article “The Challenge and Reward of Circuit Theory: Is it Really Hard?” were we give you key tips and tricks to help you in understanding and mastering circuit theory.

10. What is the role of a resistor in a circuit?

A resistor is a component used in electrical and electronic circuits to resist the flow of electrical current. It’s used to control the amount of current or to provide a voltage drop in different parts of the circuit.

11. What is a capacitor?

A capacitor is a component that stores electrical energy in an electric field. It can block direct current (DC) but allows alternating current (AC) to pass, which makes it useful in various applications like filtering noise, stabilizing power supply voltages, and tuning radio frequencies.

12. What is an inductor?

An inductor is a passive electrical component that stores energy in a magnetic field when electric current is flowing through it. Inductors are used in electronic circuits for their property of opposing a change in current.


Understanding electrical theory is like learning a new language. Because it involves becoming familiar with new terms and concepts and learning how to interpret them in the context of electrical systems. The questions and answers above provide a basic understanding of electrical theory. Once these principles are understood, they can serve as a foundation for more advanced study of electricity and electronics.

Read up on the fundamentals of electrical theory in article “Electrical Theory: Understanding the Fundamentals

Enjoy learning about electricity?