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.
Laptops use an external power supply, called a power adapter or power brick.. It converts AC to a single DC voltage that goes to the laptop's internal power supply, which generates all other required voltages. External adapters are used to reduce the size and weight of the laptop, yet they typically ride along in the laptop case, adding back the weight after all.