17 / 156
Electrical Theory & Applications for HVACR
Chapter 1: What Is Electricity?
Page 5
HOW ELECTRONS FLOW THROUGH A CONDUCTOR
Voltage is the force that causes electrons to move, but electrons cannot move unless they have a
place to go. Electrical circuits (electrical pathways) are composed of copper or aluminum wires and
devices or loads that are designed to control the flow of electrons (current). Power plants produce
EMFs, NOT electrons. The electrons are already inside the wires. The EMF produced by the power
plant forces free electrons inside the conductor to travel to the next atom within the conductor,
much like a domino effect. This electron movement from one atom to another occurs throughout the
length of the conductor. The conductors provide the necessary free electrons and provide the proper
pathway for electron movement. In a DC circuit (direct current), the electrons travel in one direcƟon
Fig. 1‐2 (a)
Fig. 1‐2 (b)
0
Fig. 1‐2 (c)
Fig. 1‐2 (d)
Fig. 1‐2 (f)
12
Fig. 1‐2 (e)