What is the difference between AEDs and defibrillators commonly used on ambulances, in hospitals, and on TV?

Defibrillators sometimes used on ambulances and in hospitals, and often seen on TV, are manual defibrillators. They are larger than AEDs and are designed to be used by medical personnel with special training. In contrast, AEDs are smaller, computerized devices designed so that virtually any operator can use them by simply following the audio and visual prompts.