| Sir William Crookes constructed this forerunner of the modern television picture tube in the 1870s to investigate the properties of cathode rays. When the tube is evacuated and a high voltage applied, one end of the tube glows, caused by cathode rays (now known to be electrons) striking the glass. The modern television picture tube, also known as a CRT (Cathode Ray Tube) is a direct descendant of the Crookes tube. The major differences are that a CRT uses a heated cathode to increase the number of electrons, while the Crookes tube does not, and the CRT has extra electrodes to focus and deflect the beam as it travels toward the screen. |
Hotmail
Messenger
My MSN
MSN Directory
