This book is a condensed explanation of power supplies used in the electronic communication industry. Chapter 1 is dedicated to linear power supply design. It includes half wave and full wave rectification, power supply ripple, regulated and unregulated supplies, capacitor multipliers, current limiting, and bootstrapping. Chapter 2 introduces switching power supply, both in theory and with actual circuits for buck, boost, flyback designs, and FCC emission requirements. Chapter 3 encompasses special power supply configurations such as diode voltage doublers and bandgap reference theory. Chapter 4 includes power generation techniques such as solar power, and wind turbines.