This type of coma is usually reversible once the blood sugar is corrected. Oxygen deprivation: Oxygen is essential for brain function. Cardiac arrest causes a sudden cutoff of blood flow and oxygen to the brain, called hypoxia or anoxia.
The external power supply is the AC power adapter that converts household AC electricity voltages to the much lower DC voltages needed to charge a mobile phone's internal battery.
Phantom power. Phantom power, in the context of professional audio equipment, is DC electric power transmitted through microphone cables to operate microphones that contain active electronic circuitry. It is best known as a convenient power source for condenser microphones, though many active direct boxes also use it.