How do electric bikes work?

Electric bicycles use batteries as a source of power and a quiet DC motor as a driving mechanism. On most e-bikes the motor is built directly into the wheel (known as a hub motor) and the batteries are discreetly hidden in the rear rack or frame. Electric bikes can be operated just like normal bicycles, but they can also be power-driven by a throttle or pedaled with the help of 'pedal-assist' (or 'PAS').