CRT monitor: description, main elements of the device

CRT-monitor – this device, which is based on a cathode-ray tube. This technology was developed in 1897 by German scientist F. brown. It was initially developed as a specialized tool designed to measure an alternating current (oscilloscope).

CRT monitor and its design

The Main element of this device is the CRT. It consists of a sealed glass tube from which you removed the air (i.e., inside vacuum). One end of the tube is flat and wide – the screen and the other is long and narrow – the neckline. The front side of the tube, the inside covered with a composition of the phosphor (on the basis of yttrium and erbium). The next element of the CRT monitor is an electron gun, which under the action of the electrostatic field beyond the stream of electrons, thereby an image appears on the screen. Elementary particles pass through a metal grate and fall on the inner side of the glass screen, coated with phosphor dots of different colors. A special deflection system ensures consistent beam field on the screen. The deflection system are of two types: saddle and toroidal. The system consists of coils placed on the neck of CRT.

The Following element that defines CRT monitor, this unit personnel and line scan. This site is the main source of interference in the working frequency range. The power consumption of these nodes, is one of the major factors that must be considered when designing a CRT monitor. The next design element is the intensity modulator, which together with the accelerating system works on the principle of the potential difference. Thanks to these nodes, the electrons acquire energy, part of which is spent on luminescence of phosphor.

RGB-technology

Typically a colour CRT monitor has 3 electron guns, and a monochrome one. These guns correspond to the primary colors: green, red and blue. Their combination can create infinite number of shades and colors. For the management of cathode ray tubes requires control electronics, which determines the quality of the monitor. It is the difference in the quality of electronics, being created by different manufacturers is a criterion for determining the difference between CRT monitors, despite the fact that the cathode ray tube is the same. So, each cannon emits a stream, which has an impact on phosphor dots of different colors. The electron beam of the same color should only effect the elements of his color. To achieve this action of the beam, use a special mask, the structure of which depends on the type of tube.

Repair of CRT monitors

The Main faults of the CRT devices are malfunction of the power supply. Most often this occurs because of the voltage drops in the mains. If failure of a power unit, most often occur concomitant breakage of other modules, for example, impaired reproduction, image distortion. In addition to surges, failures, monitors are often mechanical damage (bumps), the impact of sources of electromagnetic radiation, dust monitor, overheating, aging of the elements. Violation of the temperature regime may lead to the failure of Board video processing and system formation. The failure line scan occurs because of breakdown in high-voltage circuits and TDKS. One of the reasons of the mentioned phenomenon is the dust.