An electric circuit is a path which electrons from a voltage or current source flow. Electric current flows in a closed path called an electric circuit. The point where those electrons enter an electrical circuit is called the “source” of electrons. The point where the electrons leave an electrical circuit is called the “return” or “earth ground”. The exit point is called the “return” because electrons always end up at the source when they complete the path of an electrical circuit.

Circuits use two forms of electrical power: alternating current (AC) and direct current (DC). AC often powers large appliances and motors and is generated by power stations. DC powers battery operated vehicles and other machines and electronics. Converters can change AC to DC and vice versa. High-voltage direct current transmission uses very big converters.

 Topical Notes, Presentations, Problems, Quizzes, Tests, AP Questions and Video lessons
Introduction
Electric Resistance                                                                 
Ohm’s Law
DC Circuits with resistors only
Kirchhoff’s Laws
Series Parallel, and Series-Parallel Circuits
Capacitance
DC Circuits with Resistors and Capacitors
    Test your Understanding: Chapter 2 MCQ Quiz 1 Here                                                                                                     Take Chapter 2 ReQuiz MCQ Quiz 2 Here 
  • A circuit is an unbroken loop of conductive material that allows electrons to flow through continuously without beginning or end.
  • If a circuit is “broken,” that means its conductive elements no longer form a complete path, and continuous electron flow cannot occur in it.
  • The location of a break in a circuit is irrelevant to its inability to sustain continuous electron flow. Any break, anywhere in a circuit prevents electron flow throughout the circuit.