Circuit Theory is a branch of electrical engineering that focuses on the behavior of electrical circuits. It involves analyzing how voltage, current, and resistance interact within a circuit. Key components include resistors, capacitors, and inductors, which help determine how electrical energy is distributed and used. Understanding Circuit Theory is essential for designing and troubleshooting electronic devices. It uses mathematical models and laws, such as Ohm's Law and Kirchhoff's Laws, to predict circuit performance. This knowledge is crucial for engineers working on everything from simple household appliances to complex communication systems.