Plug-in Power Supplies
Plug-in power supplies charge mobile phones and other devices. They take power from an input source, which could be AC power mains, DC car batteries, fuel cells, a solar power converter or anything else, and pass it through the hardwired circuit connectors to the output. AC/DC plug-in adapters or chargers have their input connected to an AC power mains, and connect to the battery of the output device through hardwired cable. Some adapters may have multiple outlets. Universal AC adapters feature interchangeable input connectors and are capable of accommodating different AC mains voltages. The different types of power supplies or chargers are made in different variants, depending on the input voltage, output current and power. These factors, together with the temperature of the battery and the regulator of the device, determine the charging speed. Standard USB power supplies or chargers have a wide input voltage range and deliver a fixed or regulated output voltage, but the output voltage level depends on the model. Desktop power supplies are bigger models, used to power computers and larger devices, and serve as power backups. Power supplies or chargers meant for specific devices are rated for compatibility with the device. The form factor of the charger is an important factor in quality. Compact, low weight chargers aid portability.