The charger is the accessory that connects to your phone or laptop when the battery is low. Internal devices or batteries need a charger to keep the battery running. When you connect the laptop charger to an electrical outlet, the electric shock recharges the cells of the laptop battery. The battery charger consists of a rectifier circuit, a power supply circuit, a wave control circuit and a control circuit. You need to be careful when charging your phone as the battery can overcharge which can shorten its life. Portable chargers are an important part of mobile phone accessories.