Drawing from the author's 20+ years professional and academic experience, this book 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. Chapter topics include safety; tols for HVAC technicians; fundamentals of electricity and electrical meters; series circuits; parallel and series-parallel circuits; magnetic theory; fundamentals of AC electricity; transformers, three-phase, and single-phase voltage; symbols and diagrams for HVAC and refrigeration systems; relays, contactors, and solenoids; single-phase open motors; single-phase hermetic compressors; three-phase open motors and three-phase hermetic compressors; motor starters and overcurrent controls; thermostats and heating controls; pressure controls, timer controls, and other controls; electronic devices for HVAC systems; electrical control of heating and air-conditioning systems; electrical control of heat pump and refrigeration systems; and direct digital control systems. For service technicians, HVAC technicians, contractors, and HVAC installers.