chargers

A charger is a device that provides electrical energy to recharge a rechargeable battery or to power a device while it is operating. Chargers convert input power from sources such as mains electricity, batteries, or USB ports into the appropriate voltage and current for the target battery chemistry. They range from small wall adapters to large stationary units and from wired to wireless systems.

Wired chargers connect to devices via various interfaces, including USB-C, USB-A, Lightning, or proprietary barrel connectors. Many use switch-mode power supplies to improve efficiency and to negotiate output levels with the device. Wireless chargers transmit energy through inductive coupling, most commonly following the Qi standard, enabling charging without a direct electrical contact. Charging behavior depends on battery chemistry (for example lithium-ion, nickel-metal hydride) and may employ fast-charging profiles negotiated by the device and charger through protocols such as USB Power Delivery or other fast-charge standards.

Safety and standards: Chargers are designed to meet electrical safety requirements and regulatory standards. Protective features typically include overvoltage and overcurrent protection, short-circuit protection, temperature monitoring, and isolation. Energy-efficiency rules and certification programs are common, and many chargers minimize standby power consumption.

Applications: Chargers are used in consumer electronics such as smartphones, tablets, and laptops; in automotive contexts, including Level 1 and Level 2 AC charging and DC fast charging for electric vehicles; and in industrial or medical equipment. Portable power banks and docking stations extend charging capability and convenience.

History and trends: Charging technology evolved from simple linear adapters to efficient switch-mode supplies. The USB standard popularized universal charging for many devices, while wireless charging introduced contactless energy transfer. Ongoing developments focus on higher charging speeds, device communication for safe power negotiation, and expanded compatibility across brands.