What happens inside a device after it is turned on and powered?

After turning on the device and supplying power, several key stages occur:

1. Power supply and hardware initialization — stabilization of voltage, startup of the clock generator.

2. Bootloader execution — code from non-volatile memory (e.g., ROM or flash) runs, initializing basic hardware resources.

3. Power-On Self Test (POST) — checks of main components (memory, processor, peripherals).

4. Loading the operating system or main application — the bootloader copies the OS or program from non-volatile memory to RAM and transfers control.

5. Software initialization — setting up drivers, starting services and applications.

Thus, the device transitions from the "off" state to an operational state, ready to perform tasks.