Coaxial power conn
A coaxial power connector is a miniature power connector used for attaching extra-low voltage devices such as consumer electronics to external electricity. Also known as barrel connectors, concentric barrel connectors or tip connectors, these small cylindrical connectors come in an enormous variety of sizes.
The primary use of these plugs is as a DC connector (or sometimes AC) on the cable that comes from an external power supply. The matching jack or socket is then mounted in the equipment to be powered. Some of these jacks contain a normally closed switch; the switch can disconnect internal batteries whenever the external power supply is connected, to avoid the risk of battery leakage or explosion posed by incorrect recharging of the batteries.