Low Power, High Speed Intensity Control of CRT Electron Beam
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2005-Feb-06
A major problem with the control of the electron beam intensity in a conventional electron gun for a CRT is the large voltage applied between the cathode and the control grid to control the electron beam intensity. In addition, there is capacitance between the grid and the cathode which must be charged and discharged. At high average date rates, such as presentation of many characters on the CRT screen, the combination of the grid-cathode capacitance and the large and rapid control voltage charges contribute to large currents and high power dissipation in the video driver circuit. Finally, additional power is consumed in the heating of the cathode to high temperatures to emit electrons.