The cathode ray tube amusement device is the earliest known interactive electronic game to use a cathode ray tube (CRT). It is a device that records and controls the quality of an electronic signal. The strength of the electronic signals produced by the amusement device is controlled by knobs which influences the trajectory of the CRT's light beam. The device is purely electromechanical and does not use any memory device, computer, or programming. The player turns a control knob to position the CRT beam on the screen; to the player, the beam appears as a dot, which represents a reticle or scope. The player has a restricted amount of time in which to maneuver the dot so that it overlaps an airplane, and then to fire at the airplane by pressing a button. If the beam's gun falls within the predefined mechanical coordinates of a target when the user presses the button, then the CRT beam defocuses, simulating an explosion.
