Construction Details of CRT

1)  Electron gun:

It is very simple device which mainly produces thin electron beam. It is the combination of Heater, Cathode and the Grids. All this components are situated at the base of the tube. The heater heats the cathode and then the cathode emits a lot of electrons which make an electron cloud. The electron gun is analogous to the pen. In different parts of the electron gun different types of voltages are required. These voltages vary within the range 200-600 Volts. The electron gun receives voltages from the receiver which is connected with the base pins of the CRT.

2) Heater:

The heater is mainly used to heat the cathode. It is made of metals and twisted in shape. It heats the cathode indirectly. It needs 6-24 Volts dc or ac supply voltage.

Cathode Ray Tube

The Cathode Ray Tube is an optoelectronic device. That is it converts electrical signal into video signal. Physically it is a large, hard and evacuated glass tube.

In most optical devices, it posses most of the places. Actually it is the heart of an oscilloscope and is very similar to the picture tube of Television Set, Computer Monitor etc. with a view to saving space in TV set it is designed with a narrow neck and a large deflection angle. In the narrow neck it contains most of the important components for processing the signal. The tubes are usually designated by the maximum deflection angle and the length along the diagonal of the screen.

CRT has two main parts.

      1)   Base/Low voltage side (<1 KV)

      2)   Anode/High voltage side (> several KV)

 The base or low voltage side also contains the following parts: 

      1)   Electron Gun

      2)   Heater

      3)   Cathode

      4)   Grids