For undergraduate courses in Principles of Heating, Ventilating, AC/Refrigeration, Electricity and Electronics for HVAC and Controls for HVAC.Drawing from the author's 20+ years professional and academic experience, this text presents basic AC and DC electricity, electrical principles, electric circuits and controls for air conditioning, heating and refrigeration systems. It is specifically designed to be clear and concise enough for beginners--with a straightforward writing style and numerous diagrams and illustrations--yet comprehensive and accessible enough to serve as a professional reference.