Charger

About chargers and power supplies

Devices that are commonly referred to as “chargers” are technically power supplies. A power supply provides a fixed voltage and defines the maximum current it can deliver. For example, USB ports on a PC can support different maximum current levels depending on the port type, such as 500 mA, 900 mA, 1.5 A, or up to 3 A.

However, the connected device does not automatically draw the maximum current available. Instead, the receiving device controls how much current it draws, effectively regulating the current flow according to its own requirements.

A charger, in the strict technical sense, is the circuit that controls the voltage and current delivered to a battery. This charging circuit is usually built into the device itself, such as in smartphones or portable audio devices, which is why it is often referred to as a built-in charger.

The built-in charger continuously manages the charging process by adjusting the current supplied to the battery. When charging is required, it allows current to flow; once the battery is fully charged, it stops the current flow to prevent overcharging.