POWER POINT PRESENTATION ON PICTURE TUBE SUB:AUDIO VIDEO SYSTEM

GUIDED BY… ASST.PROF. :- M K VALA PRESENTED BY… NAME:BANDIYAWALA SAHIL R. ENROLLMENT NO: 130430111007 ROLL NO: 4018 GUIDED BY… ASST.PROF. :- M K VALA

Picture Tubes Introduction Picture Tube Monochrome Tube Color picture tube

What is Picture Tube ??? The picture tube is very similar to the cathode-ray tube used in an oscilloscope. The glass envelope contains an electron Gun structure that produces a beam of electrons aimed at the fluorescent screen. When the electron beam strikes the screen, light is emitted.

Picture Tube FIGURE 1.1 PICTURE TUBE

Monochrome Tube A monochrome picture tube has one electron gun and a continuous phosphor coating that produces a picture in black and white. For colour picture tubes the screen is formed of three different phosphors and there are three electron beams, one for each colour phosphor. The three colours are red, green and blue produced by three phosphors combined to produce different colours.

Monochrome Picture Tube FIGURE: 1.2 MONOCHROME PICTURE TUBE

COLOUR TELEVISION DISPLAY TUBES The object is to produce three coincident rasters with produce the red, green and blue contents of the transmitted picture. While seeing from a normal viewing distance the eye integrates the three colour information to convey the sensation of the hue at each part of the picture.

ELECTROSTATIC FOCUSSING The electric field due to the positive potential at the accelerating grid extends through the opening the of the control grid right to the cathode surface. The orientation of this field is such that besides accelerating electrons down the tube. It also brings all the electrons in the stream into a tiny spot called the cross over. This is known as the first electrostatic lens action. The electrode voltages are so chosen or the electric field is so varied that the second point where all the electrons get focused is the screen of the picture tube. Electrostatic focusing is preferred over magnetic focusing because it is not affected very much by changes in the line voltage.

Based on the gun configuration and the manner in which phosphors are arranged on the screen, three different types of colour picture tubes have been developed. These are:- 1. Delta gun 2. Precision in line 3. Trintron Colour

TYPES OF PICTURE TUBES THERE ARE THREE TYPES OF PICTURETUBES.. 1. DELTA GUN 2. PRECISION IN LINE 3. TRINTRON PICTURETUBE

WHAT IS DELTA GUN PICTURE TUBE ??? This tube was developed by Radio Corporation on America. It employs three separate guns on for each phosphor. The guns are equally spaced at 120 degree interval with respect to each other and tilted inwards in relation to the axis of the tube. They form an equilateral triangular configuration.

DELTA GUN PICTURE TUBE FIGURE 1.3 DELTA GUN COLOUR PICTURE TUBE

WHAT IS PRECISION IN LINE COLOR PICTURE TUBE WHAT IS PRECISION IN LINE COLOR PICTURE TUBE??? This tube as the name suggests has three guns which are aligned precisely in a horizontal line. The gun and mask structure of the P.I.L tube together with yoke mounting. The inline gun configuration helps in simplifying conversions adjustments.

WHAT IS PRECISION IN LINE COLOR PICTURE TUBE??? The color phosphors are deposited on the screen in the form of vertical strips in triads which are repeated along the breadth of the tube. To obtain the same color, finest as in a delta gun tube the horizontal spacing between the strips of the same color in adjacent traids is made equal to that between the dots of the same color in the delta gun tube.

PRECISION IN LINE FIGURE 1.4 PRECISION IN LINE COLOUR PICTURE TUBE

TRINTRON COLOR PICTURE TUBE FIGURE 1.5 TRINTRON COLOR PICTURE TUBE

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