# 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://doc-kr.qudelix.com/general/charger.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.