Important components of a Cathode ray Tube.

A Cathode ray Tube or in short CRT is a significant technological development in the field of science. CRT is a display system, which generates images in the form of video signals. It is a specialized vacuum tube, where images are produced when beams of electrons strike the phosphorescent screen surface. The electron Gun, Control Electrode, Focusing system, Deflection plates, Phosphorous coated screen, graticule, etc. are important components of a Cathode ray Tube.

What is a Cathode ray Tube?

A Cathode ray Tube or in short CRT is a significant technological development in the field of physics. CRT is a display system, which generates images in the form of video signals. It is a specialized vacuum tube, made up of thick glass, capable of producing images when beams of electrons through electron guns strike the phosphorescent screen surface.

When highly accelerated electron beams strike the phosphorescent screen, the beam becomes visible and images are seen. The different colors seen on the screen are due to a blend of red, blue, and green light. The important components of a Cathode ray Tube include Connecting pins, an electron Gun, Control Electrode, a Focusing system, etc.

Eugen Goldstein, the German physicist in 1870 conducted his own dischargeable tube experiments and coined the term Kathodenstrahlen or cathode ray.

Important components of a Cathode ray Tube;

The important components of a Cathode ray Tube include Connecting pins, an electron Gun, Control Electrode, a Focusing system, Deflection plates, a Phosphorous coated screen, a graticule, etc. All the components make the Cathode ray Tube functional.

Connecting pins:

Connecting pins are one of the important components of a Cathode ray Tube. Such pins are concealed and internally connected to the different electrodes inside the Cathode ray Tube. These pins are also for external connection for the power supply.

Base:

A cathode ray tube creates a vacuum space inside after all the electrodes are fitted and it is closed by sealing at the base.

Electron Gun:

The electron gun is a vital and one of the important components of a Cathode ray Tube. It contains a number of elements including a heating filament, cathode, etc.

The heating filament or heater is an element made up of resistive material such as a tungsten coil. It is used to heat up the cathode, whereas the cathode produces the electron beams.

The cathode is made up of thick copper being closed at one side and is connected to a high negative voltage. The electron beam produced is focused on the face of CRT through a narrow path of the control grid.

Control Grid:

Control Grid is made up of thick copper which covers the cathode. Its function is to control the number of electrons in the electron beam. Control Grid contains a tiny hole at its center The electrons released from the cathode, pass through the hole and are separated due to mutual repulsion.

The anodes:

One of the important components of a cathode ray tube is the anode. CRT contains three anodes of hollow cylinder shapes. The anodes are used to accelerate the electron’s focus on the screen. Further, they receive secondary electrons emitted by the phosphor particles of CRT. The anodes are fitted to the positive voltage from left to right in decreasing order.

Deflection plate:

CRT contacts two pairs of deflection plates placed each pair vertically and horizontally. They are used to control the electron beam. The vertical deflection plates deflect the electron beam on the screen along the horizontal plane for horizontal deflection whereas the horizontal deflection plates do the same on the vertical plane for vertical deflection when the voltage is applied across it.

The horizontal and vertical movement of electrons is independent of each other, causing the beam to be positioned at anywhere on the screen. Deflection plates are definitely one of the important components of a cathode ray tube.

Aquadag coating:

It is a thin metallic coating made in the inner portion of a cathode ray tube. Aquadag coating is used to absorb all the electrons that bounced back after hitting the screen to keep it(the screen) in the state of electrical equilibrium.

Screen coated with phosphorus:

A CRT is fitted with a screen on its front end. The inside front surface of a CRT is coated with phosphorus. The phosphorus-coated screen generates light when it is hit by a high-energy electron beam.

Graticule:

The graticule is one of the important components of a cathode ray tube used as a measurement scale. It may be a transparent external plate made of glass or an acrylic sheet. With the use of graticule displacement of an electron beam on screen is measured along with the study of other parameters.

Types of CRT and uses:

CRT can be of two types Monochrome or color. In monochrome one electron gun is fitted whereas in color type three electron guns are fitted to produce the red, green, and blue images. The combination of three colors produces multicolor images. Monochrome type of CRT generates black and white images.

A CRT is used in a television set called a picture tube and in the computer monitor. It is also used as a memory device and in the oscilloscope.

Conclusion:

A CRT technology developed in the late 19th century made television and computer monitor memorable. The important components of a Cathode ray Tube include Connecting pins, an electron Gun, Control Electrode, a Focusing system, Deflection plates, a Phosphorous coated screen, a graticule, etc made the CRT functional. Further technological evolution made CRTs obsolete since the middle of the 21st century and replaced them with LED and plasma displays etc. But still found its application in an oscilloscope and computer display.