The straightforward translation is "включен" (= switched on). However, it depends heavily on the context.

"Включен" is typically used for electrically powered components. For mechanical devices the preferred translation would most likely be "работи" (= is operating) – which is also more general and can be used in most contexts, regardless of the component type.

It also depends on whether the component is actually operating (performing certain actions) or simply activated (i.e. power supply is on but the component remains in standby or similar mode). In this case it might be more appropriate to use "активен" or "активиран" (= active / activated).