Question: what are commonest types of output device?
Answer: The most common output device is the monitor or VDU. Modern monitors, where the case isn't more than a few centimetres deep, are usually Liquid Crystal Displays (LCD) or Thin Film Transistors (TFT) monitors. Older monitors, where the case is likely to be around 30 cm deep, are Cathode Ray Tube (CRT) monitors.